6 ms·

Tell HN: Most DisplayPort cables aren't sold with correct information

159 points by bloopernova 4y ago

In every DisplayPort (DP) cable I've seen on Amazon and many other retailers, the main difference between cables is shown as the version of the DP specification that they support. Unfortunately, that's not what makes a DP cable different from its peers. Every DP cable supports every version of the spec! 1.1 to 1.4, they all support the same DP spec. The difference is in the bandwidth they support: RBR, HBR, HBR2, HBR3, and UHBR 10 (and above). This then translates to the resolution and refresh rate that the cable can support. The differences are listed here: https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_and_certifications https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_an... RBR (Reduced Bit Rate) 6.48 Gbit/s HBR (High Bit Rate) 10.80 Gbit/s HBR2 (High Bit Rate 2) 21.60 Gbit/s HBR3 (High Bit Rate 3) 32.40 Gbit/s UHBR 10 (Ultra High Bit Rate 10) 40.00 Gbit/s The Wikipedia page also has tables that show what those bandwidths are capable of with regards to resolution+refresh rate: https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_common_resolutions https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_... If you want 4K @ 60Hz you need a HBR2 cable. For 4K @ 144Hz you need UHBR 10. Some retailers are better at telling you what bandwidth their cables support, such as Startech which does list the BR: https://www.startech.com/en-us/search?search_term=HBR3 https://www.startech.com/en-us/search?search_term=HBR3 Monoprice doesn't show any search results for HBR3: https://www.monoprice.com/search/index?keyword=HBR3&didyoumean=HBR3&TotalProducts=37 https://www.monoprice.com/search/index?keyword=HBR3&didyoume... Cable Matters does have some results, but doesn't show the bitrate in the product title: https://www.cablematters.com/search.aspx?PageSize=20&PageNum=1&SearchTerm=HBR3 https://www.cablematters.com/search.aspx?PageSize=20&PageNum... Amazon shows results for HBR3 but so many customer reviews tell of counterfeit cables and straight up lying in descriptions. If you know of any better retailers that sell UHBR 10 or above cables, please let me know in the comments! I hope this information is useful to someone and saves you some time and pain trying different cables.

bloopernova 4y ago
Cable Matters, to its credit, does have some discussion of the higher bitrate cables and their availability towards the end of this year: https://www.cablematters.com/Blog/DisplayPort/displayport-2-0-certification-what-are-dp40-and-dp80-cables https://www.cablematters.com/Blog/DisplayPort/displayport-2-...
- hadlock 4y ago
  When it comes to buying commodity type electronics, cable matters and anker are just about the only two brands I'll trust/buy unless it's something extremely generic like RCA cables or a 3.5mm headphone adapter
eimrine 4y ago
I have several DP cables, using it with no problems on 2560x1080. How to figure up which standard they are?
- bloopernova 4y ago
  Look at this table: https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_common_resolutions https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_... Depending on the refresh rate, your cables are probably HBR.
- tverbeure 4y ago
  2560x1080 has very low bandwidth requirements. At 60Hz even RBR works! Your cable would have to be almost completely broken for it not to work. My video timings calculator shows exactly what kind of minimum protocol you need for a given video timing. https://tomverbeure.github.io/video_timings_calculator https://tomverbeure.github.io/video_timings_calculator
  - bloopernova 4y ago
    Oh wow, that's really useful, thank you!
- izacus 4y ago
  Pretty much any cable will work at that resolution. Problems usually happen at 4K resolutions, UWD resolutions (e.g. 3440x1440 and over) and especially at refresh rates over 60Hz.
PaulKeeble 4y ago
A few tech youtubers have noted the problem before with cables and a lack of specifications and many cables not meeting the specs they do list. Amazon is flooded with knock offs with brands that last a month at this point, you will get your money back if it doesn't work as specified but its frustrating that it continues. I think the problem is even wider than displayport/HDMI cables. It extends to hubs and everything USB as well, the bulk of stuff is sold with very little information compared to the actual specs, most hubs are USB 3.0, a type C connector wont say what parts of the standards it accepts etc etc. Its become an increasing problem on laptops as well, you have USB C ports that may or may not pass displayport and its really unclear at what speed they can do that with the manufacturers refusing to list the specs or even answer the questions. The specifications have never been more complex and convoluted and it really makes it look like the standards process has been corrupted to be able to sell substandard equipment. This only hurts their brand and customers however who find it hard to get what they want. I would say it starts in the specifications but honestly while convoluted with too many optional parts its the sales end that refuses to accurately portray what their products can do. Its a giant mess at the moment and I don't see any signs its going to get anything but worse.
- bloopernova 4y ago
  Yeah agreed on the USB spec. I have a CaberQU USB-C cable tester via Kickstarter, which I can use to see what pins are connected and from there at least guess what they support. Unfortunately the CaberQU site is down right now, but the Kickstart page is still up: https://www.kickstarter.com/projects/electr/c2c-caberqu-usb-c-cable-tester/description https://www.kickstarter.com/projects/electr/c2c-caberqu-usb-... I'd love to see something similar for DisplayPort, HDMI and more.
noinsight 4y ago
Yeah these cables are definitely a minefield… The solution is to look for an officially certified cable, they will work as advertised. Displayport.org has a database of certified products. I already ran into this in 2016 when I got my 4K display. I looked up a certified cable and bought it off Amazon. Worked perfectly as expected. Same applies to HDMI at more demanding bandwidths.
- gh02t 4y ago
  I got two certified HDMI cables at Walmart (and cross referenced the certification online). One of them worked fine, while the other one worked in a basic sense but failed to negotiate and wouldn't give me all the fancy sound and video options going from my Shield to my LG TV. The other cable, nominally identical, worked fine swapping between them so the other one must have been bad and I ended up returning it for another one that worked. So even the certified cables can be defective it seems, and more confusing is that they still mostly work. The defective cable would still negotiate 4K and show a nice image, but wouldn't work with stuff like Dolby Vision (and a couple other more advanced modes but that is the one I remember). I probably would have just assumed something else was wrong with my setup and written it off if I hadn't bought an identical cable to swap. I bet a lot of people wouldn't even notice the missing functionality, which is likely how this has become so widespread.
FeistySkink 4y ago
What happens if a cables doesn't have enough bandwidth for a resolution/refresh rate combo?
- thefz 4y ago
  Usually the reported maximum res/rate is lower.
- tverbeure 4y ago
  The source and the sink negotiate a link rate that allows error free communication, based on the number of errors seen on a known pattern over a certain amount of time during the link training phase. When the established link rate is too low for a requested video timing, the source requests a less demanding video rate. It’s why the control panel of a GPU might now show the video timing that your monitor officially supports. In modern GPUs and monitors, an alternative is that DSC (display stream compression) is used, and that the compression ratio is cranked up to still fit the requested timing in a reduced availabile bandwidth. The image quality impact is usually unnoticeable.
  - formerly_proven 4y ago
    Normal DP cables in particular are entirely passive, there is no chip or coding in them that would tell source/sink what kind of cable it is. IME the most likely result of a marginal cable will be that the screen sometimes goes black for 1-2 seconds or shows an artifact here or there. With DVI, which just directly blasted red/green/blue bits on separate wires at the pixel clock (bad for EMI) it was pretty easy to end up with a cable that had issues just on the twisted pair for a particular color.
    - tverbeure 4y ago
      Yes, I know they are entirely passive. That’s why the source and sink need to determine the maximum rate literally based on trial and error. The source tries a link speed (and other parameters such as drive strength and pre-emphasis), the sink reports back home many symbol errors it detected. Rinse repeat until a stable configuration is found. For marginal connections that’s often not sufficient. After the introduction of DSC, DP has mandatory support for Reed-Solomon forward error correction, which is a great help in fixing occasional error burst. It can be enabled when DSC is off, but I don’t know that happens in practice.
bloopernova 4y ago
Apologies for the links not working in the post. Here's every link: https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_and_certifications https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_an... https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_common_resolutions https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_... https://www.startech.com/en-us/search?search_term=HBR3 https://www.startech.com/en-us/search?search_term=HBR3 https://www.monoprice.com/search/index?keyword=HBR3&didyoumean=HBR3&TotalProducts=37 https://www.monoprice.com/search/index?keyword=HBR3&didyoume... https://www.cablematters.com/search.aspx?PageSize=20&PageNum=1&SearchTerm=HBR3 https://www.cablematters.com/search.aspx?PageSize=20&PageNum...
cainxinth 4y ago
LTT got a TotalPhase cable tester and ran tests on a whole bunch of video cables. Lots of cables from major suppliers like Monoprice failed their tests. Here’s the video for DisplayPort: https://www.youtube.com/watch?v=Vn2vdQZhs0w https://www.youtube.com/watch?v=Vn2vdQZhs0w
- altairprime 4y ago
  Thanks for this link. The results spreadsheet has “UHBR10 passed” in the Notes column for those that did: https://docs.google.com/spreadsheets/d/e/2PACX-1vQ1maB_K91AwicWl-I7aBgOn2FrJPqsVuGHTw3LWLesO1r9bgDN8o7O3ynXk0WFO7y5iE0-8xJ1TR1p/pubhtml?lsrp=1# https://docs.google.com/spreadsheets/d/e/2PACX-1vQ1maB_K91Aw...
  - vxNsr 4y ago
    This is why I’m curious to see how LTT will be able to properly monetize their new review unit, for most ppl it’s not interesting to see HOW the widgets were reviewed, they just want to see the results. If the results exist in any form other than the video most people who don’t have time for a video will just skip to going to the webpage that contains the results. And in the case of a gdocs page there’s no ad revenue to monetize those people… so this kinda creates a situation that calls for either gatekeeping like consumer reports or forcing everyone to watch a video and not creating these nice lists which is semi anti-consumer.
    - Operyl 4y ago
      They've already stated it's going to have a pretty robust website with good search engine to filter through their test results and blog posts. Then they'll take certain tests and make videos on top of that for the main channel, otherwise they'll be pretty independent business units.
      - vxNsr 4y ago
        Got it, so it’ll be very different. Monetization will likely be affiliate links and ads, though I wonder if they’ll give float plane subscribers an ad free experience. Also curious if they’ll be able to keep the firewall between marketing and review that it appears wirecutter has failed to do.
andix 4y ago
Same problem with USB-C cables. It’s really hard to find out if it can only charge your phone, or if you can also connect a screen with it (DP).
- stormbrew 4y ago
  The easiest way to guarantee these things is to get thunderbolt 3 or 4 cables if you want to have anything beyond basic USB 2 or 3 features. They generally have a lightning bolt on the plug casing.
  - k8sToGo 4y ago
    But that implies overpaying for a cable.
    - stormbrew 4y ago
      If you're literally only using it to carry DP? I suppose. If you're actually using it as a docking cable and you're expecting it to carry usb, video, and power then I think you might have really unreasonable expectations of what it takes to carry all that in one cable and how cheap that's ever likely to be.
      - k8sToGo 4y ago
        I never said it has to be cheap. I said you are over paying because you might be paying for features that you don't use.
        stormbrew 4y ago
        I don't think that's really accurate. A passive low bandwidth tb3 cable is basically just a usb3 cable with a defined set of capabilities and a certification. OP wanted power and video, that's what a tb3 cable provides.
  - andix 4y ago
    I know. But they are very short. I think an usb 3 cable can be up to 2 meters. Thunderbolt just 0.8 or something.
lnxg33k1 4y ago
Coolblue has a result https://www.coolblue.nl/en/share-product/834931?utm_medium=ios-app&utm_source=referral&utm_campaign=product-share https://www.coolblue.nl/en/share-product/834931?utm_medium=i... Megekko instead has a lot of results https://www.megekko.nl/?r=cdromland https://www.megekko.nl/?r=cdromland But is a shop focused on pc components so it’s less generic
Tomdarkness 4y ago
Personally with DP cables, especially if you're looking for a longer length cable or wanting to push a higher bit rate through it, then you're better off just spending a bit extra and getting a proper VESA certified cable.
- simcop2387 4y ago
  Along with that, I've found that fiber based cables tend to be more reliable than the copper ones. I suspect this is because the media conversion causes there to be a cleaner signal at the output since it has to completely recreate it rather than just amplifying it. Leading to better clocking and less rounding of the edges from capacitance of the cable.
seanalltogether 4y ago
Most of the cables I've purchased always list the max resolution, so if a cable says 4k@60hz I would assume it's HBR2
da768 4y ago
I've had good experience with Accell cables so far, they're usually well rated and have proper certification. They do sell HBR3 cables, but nothing more than an announcement for UHBR cables. EDIT: Club3D is also one of the rare brands selling VESA-certified cables
CharlesW 4y ago
> Monoprice doesn't show any search results for HBR3: You can (at least partially) chalk this up to a bad search engine. Individual listings (e.g. https://www.monoprice.com/product?p_id=37920 https://www.monoprice.com/product?p_id=37920) appear to specify supported transmission rates. Here's an excerpt from that page: • Supports High Bit Rate 3 (HBR3) • Delivers up to 32.4 Gbps data bandwidth • Supports Display Stream Compression 1.2 (DSC) visually lossless compression
city41 4y ago
Does this apply to DisplayPort KVM switches too? I would think so? I have a DP KVM switch that won't let me run my monitors at their highest resolution, this probably explains it.
avip3d 4y ago
VESA has a list of certified and tested cables (limited #) but if you can go for those ones, it's worth it!
winrid 4y ago
Suggestions on a good USB C to DP for 4k+ @ 144hz? I have a 49" ultrawide and super hard to get MacBook to work properly.
- bloopernova 4y ago
  Sorry, I only just saw this! Cable Matters: https://www.cablematters.com/pc-1278-154-vesa-certified-displayport-14-cable-18m.aspx https://www.cablematters.com/pc-1278-154-vesa-certified-disp... plus this adapter: https://www.cablematters.com/pc-1038-122-usb-c-to-displayport-adapter-8k-ready.aspx https://www.cablematters.com/pc-1038-122-usb-c-to-displaypor... I'm using these 2 items to get 4K @ 120Hz on my Acer screen, from my intel macbook.
  - winrid 4y ago
    Thank you! No need to apologize, you don't have any obligations lol

159 points by bloopernova 4y ago

bloopernova 4y ago

Cable Matters, to its credit, does have some discussion of the higher bitrate cables and their availability towards the end of this year: https://www.cablematters.com/Blog/DisplayPort/displayport-2-0-certification-what-are-dp40-and-dp80-cables https://www.cablematters.com/Blog/DisplayPort/displayport-2-...

hadlock 4y ago
When it comes to buying commodity type electronics, cable matters and anker are just about the only two brands I'll trust/buy unless it's something extremely generic like RCA cables or a 3.5mm headphone adapter

eimrine 4y ago

I have several DP cables, using it with no problems on 2560x1080. How to figure up which standard they are?

bloopernova 4y ago
Look at this table: https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_common_resolutions https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_... Depending on the refresh rate, your cables are probably HBR.
tverbeure 4y ago
2560x1080 has very low bandwidth requirements. At 60Hz even RBR works! Your cable would have to be almost completely broken for it not to work. My video timings calculator shows exactly what kind of minimum protocol you need for a given video timing. https://tomverbeure.github.io/video_timings_calculator https://tomverbeure.github.io/video_timings_calculator
- bloopernova 4y ago
  Oh wow, that's really useful, thank you!
izacus 4y ago
Pretty much any cable will work at that resolution. Problems usually happen at 4K resolutions, UWD resolutions (e.g. 3440x1440 and over) and especially at refresh rates over 60Hz.

PaulKeeble 4y ago

A few tech youtubers have noted the problem before with cables and a lack of specifications and many cables not meeting the specs they do list. Amazon is flooded with knock offs with brands that last a month at this point, you will get your money back if it doesn't work as specified but its frustrating that it continues. I think the problem is even wider than displayport/HDMI cables. It extends to hubs and everything USB as well, the bulk of stuff is sold with very little information compared to the actual specs, most hubs are USB 3.0, a type C connector wont say what parts of the standards it accepts etc etc. Its become an increasing problem on laptops as well, you have USB C ports that may or may not pass displayport and its really unclear at what speed they can do that with the manufacturers refusing to list the specs or even answer the questions. The specifications have never been more complex and convoluted and it really makes it look like the standards process has been corrupted to be able to sell substandard equipment. This only hurts their brand and customers however who find it hard to get what they want. I would say it starts in the specifications but honestly while convoluted with too many optional parts its the sales end that refuses to accurately portray what their products can do. Its a giant mess at the moment and I don't see any signs its going to get anything but worse.

bloopernova 4y ago
Yeah agreed on the USB spec. I have a CaberQU USB-C cable tester via Kickstarter, which I can use to see what pins are connected and from there at least guess what they support. Unfortunately the CaberQU site is down right now, but the Kickstart page is still up: https://www.kickstarter.com/projects/electr/c2c-caberqu-usb-c-cable-tester/description https://www.kickstarter.com/projects/electr/c2c-caberqu-usb-... I'd love to see something similar for DisplayPort, HDMI and more.

noinsight 4y ago

Yeah these cables are definitely a minefield… The solution is to look for an officially certified cable, they will work as advertised. Displayport.org has a database of certified products. I already ran into this in 2016 when I got my 4K display. I looked up a certified cable and bought it off Amazon. Worked perfectly as expected. Same applies to HDMI at more demanding bandwidths.

gh02t 4y ago
I got two certified HDMI cables at Walmart (and cross referenced the certification online). One of them worked fine, while the other one worked in a basic sense but failed to negotiate and wouldn't give me all the fancy sound and video options going from my Shield to my LG TV. The other cable, nominally identical, worked fine swapping between them so the other one must have been bad and I ended up returning it for another one that worked. So even the certified cables can be defective it seems, and more confusing is that they still mostly work. The defective cable would still negotiate 4K and show a nice image, but wouldn't work with stuff like Dolby Vision (and a couple other more advanced modes but that is the one I remember). I probably would have just assumed something else was wrong with my setup and written it off if I hadn't bought an identical cable to swap. I bet a lot of people wouldn't even notice the missing functionality, which is likely how this has become so widespread.

FeistySkink 4y ago

What happens if a cables doesn't have enough bandwidth for a resolution/refresh rate combo?

thefz 4y ago
Usually the reported maximum res/rate is lower.
tverbeure 4y ago
The source and the sink negotiate a link rate that allows error free communication, based on the number of errors seen on a known pattern over a certain amount of time during the link training phase. When the established link rate is too low for a requested video timing, the source requests a less demanding video rate. It’s why the control panel of a GPU might now show the video timing that your monitor officially supports. In modern GPUs and monitors, an alternative is that DSC (display stream compression) is used, and that the compression ratio is cranked up to still fit the requested timing in a reduced availabile bandwidth. The image quality impact is usually unnoticeable.
- formerly_proven 4y ago
  Normal DP cables in particular are entirely passive, there is no chip or coding in them that would tell source/sink what kind of cable it is. IME the most likely result of a marginal cable will be that the screen sometimes goes black for 1-2 seconds or shows an artifact here or there. With DVI, which just directly blasted red/green/blue bits on separate wires at the pixel clock (bad for EMI) it was pretty easy to end up with a cable that had issues just on the twisted pair for a particular color.
  - tverbeure 4y ago
    Yes, I know they are entirely passive. That’s why the source and sink need to determine the maximum rate literally based on trial and error. The source tries a link speed (and other parameters such as drive strength and pre-emphasis), the sink reports back home many symbol errors it detected. Rinse repeat until a stable configuration is found. For marginal connections that’s often not sufficient. After the introduction of DSC, DP has mandatory support for Reed-Solomon forward error correction, which is a great help in fixing occasional error burst. It can be enabled when DSC is off, but I don’t know that happens in practice.

bloopernova 4y ago

Apologies for the links not working in the post. Here's every link: https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_and_certifications https://en.wikipedia.org/wiki/DisplayPort#Cable_bandwidth_an... https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_common_resolutions https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_... https://www.startech.com/en-us/search?search_term=HBR3 https://www.startech.com/en-us/search?search_term=HBR3 https://www.monoprice.com/search/index?keyword=HBR3&didyoumean=HBR3&TotalProducts=37 https://www.monoprice.com/search/index?keyword=HBR3&didyoume... https://www.cablematters.com/search.aspx?PageSize=20&PageNum=1&SearchTerm=HBR3 https://www.cablematters.com/search.aspx?PageSize=20&PageNum...

cainxinth 4y ago

LTT got a TotalPhase cable tester and ran tests on a whole bunch of video cables. Lots of cables from major suppliers like Monoprice failed their tests. Here’s the video for DisplayPort: https://www.youtube.com/watch?v=Vn2vdQZhs0w https://www.youtube.com/watch?v=Vn2vdQZhs0w

altairprime 4y ago
Thanks for this link. The results spreadsheet has “UHBR10 passed” in the Notes column for those that did: https://docs.google.com/spreadsheets/d/e/2PACX-1vQ1maB_K91AwicWl-I7aBgOn2FrJPqsVuGHTw3LWLesO1r9bgDN8o7O3ynXk0WFO7y5iE0-8xJ1TR1p/pubhtml?lsrp=1# https://docs.google.com/spreadsheets/d/e/2PACX-1vQ1maB_K91Aw...
- vxNsr 4y ago
  This is why I’m curious to see how LTT will be able to properly monetize their new review unit, for most ppl it’s not interesting to see HOW the widgets were reviewed, they just want to see the results. If the results exist in any form other than the video most people who don’t have time for a video will just skip to going to the webpage that contains the results. And in the case of a gdocs page there’s no ad revenue to monetize those people… so this kinda creates a situation that calls for either gatekeeping like consumer reports or forcing everyone to watch a video and not creating these nice lists which is semi anti-consumer.
  - Operyl 4y ago
    They've already stated it's going to have a pretty robust website with good search engine to filter through their test results and blog posts. Then they'll take certain tests and make videos on top of that for the main channel, otherwise they'll be pretty independent business units.
    - vxNsr 4y ago
      Got it, so it’ll be very different. Monetization will likely be affiliate links and ads, though I wonder if they’ll give float plane subscribers an ad free experience. Also curious if they’ll be able to keep the firewall between marketing and review that it appears wirecutter has failed to do.

andix 4y ago

Same problem with USB-C cables. It’s really hard to find out if it can only charge your phone, or if you can also connect a screen with it (DP).

stormbrew 4y ago
The easiest way to guarantee these things is to get thunderbolt 3 or 4 cables if you want to have anything beyond basic USB 2 or 3 features. They generally have a lightning bolt on the plug casing.
- k8sToGo 4y ago
  But that implies overpaying for a cable.
  - stormbrew 4y ago
    If you're literally only using it to carry DP? I suppose. If you're actually using it as a docking cable and you're expecting it to carry usb, video, and power then I think you might have really unreasonable expectations of what it takes to carry all that in one cable and how cheap that's ever likely to be.
    - k8sToGo 4y ago
      I never said it has to be cheap. I said you are over paying because you might be paying for features that you don't use.
      - stormbrew 4y ago
        I don't think that's really accurate. A passive low bandwidth tb3 cable is basically just a usb3 cable with a defined set of capabilities and a certification. OP wanted power and video, that's what a tb3 cable provides.
- andix 4y ago
  I know. But they are very short. I think an usb 3 cable can be up to 2 meters. Thunderbolt just 0.8 or something.

lnxg33k1 4y ago

Coolblue has a result https://www.coolblue.nl/en/share-product/834931?utm_medium=ios-app&utm_source=referral&utm_campaign=product-share https://www.coolblue.nl/en/share-product/834931?utm_medium=i... Megekko instead has a lot of results https://www.megekko.nl/?r=cdromland https://www.megekko.nl/?r=cdromland But is a shop focused on pc components so it’s less generic

Tomdarkness 4y ago

Personally with DP cables, especially if you're looking for a longer length cable or wanting to push a higher bit rate through it, then you're better off just spending a bit extra and getting a proper VESA certified cable.

simcop2387 4y ago
Along with that, I've found that fiber based cables tend to be more reliable than the copper ones. I suspect this is because the media conversion causes there to be a cleaner signal at the output since it has to completely recreate it rather than just amplifying it. Leading to better clocking and less rounding of the edges from capacitance of the cable.

seanalltogether 4y ago

Most of the cables I've purchased always list the max resolution, so if a cable says 4k@60hz I would assume it's HBR2

da768 4y ago

I've had good experience with Accell cables so far, they're usually well rated and have proper certification. They do sell HBR3 cables, but nothing more than an announcement for UHBR cables. EDIT: Club3D is also one of the rare brands selling VESA-certified cables

CharlesW 4y ago

> Monoprice doesn't show any search results for HBR3: You can (at least partially) chalk this up to a bad search engine. Individual listings (e.g. https://www.monoprice.com/product?p_id=37920 https://www.monoprice.com/product?p_id=37920) appear to specify supported transmission rates. Here's an excerpt from that page: • Supports High Bit Rate 3 (HBR3) • Delivers up to 32.4 Gbps data bandwidth • Supports Display Stream Compression 1.2 (DSC) visually lossless compression

city41 4y ago

Does this apply to DisplayPort KVM switches too? I would think so? I have a DP KVM switch that won't let me run my monitors at their highest resolution, this probably explains it.

avip3d 4y ago

VESA has a list of certified and tested cables (limited #) but if you can go for those ones, it's worth it!

winrid 4y ago

Suggestions on a good USB C to DP for 4k+ @ 144hz? I have a 49" ultrawide and super hard to get MacBook to work properly.

bloopernova 4y ago
Sorry, I only just saw this! Cable Matters: https://www.cablematters.com/pc-1278-154-vesa-certified-displayport-14-cable-18m.aspx https://www.cablematters.com/pc-1278-154-vesa-certified-disp... plus this adapter: https://www.cablematters.com/pc-1038-122-usb-c-to-displayport-adapter-8k-ready.aspx https://www.cablematters.com/pc-1038-122-usb-c-to-displaypor... I'm using these 2 items to get 4K @ 120Hz on my Acer screen, from my intel macbook.
- winrid 4y ago
  Thank you! No need to apologize, you don't have any obligations lol