5 ms·

That 5950X (and its predecessor) seem like voodoo with the core count, clock frequency, and TDP (yes, I know TDP is a flawed, flawed number - it's still impress

That 5950X (and its predecessor) seem like voodoo with the core count, clock frequency, and TDP (yes, I know TDP is a flawed, flawed number - it's still impressive).

bob1029 6y ago
I second this reaction. Historically, clock speeds scaled inversely with the # of cores. Seems like the efficiency is overtaking other constraints at this point.
- deleted 6y ago
  [deleted]
- loeg 6y ago
  The achievable all-core clock will inevitably scale inversely with # of cores, in practice. The advertised single core and all-core clocks are some combination of binning and pure marketing.
  - greggyb 6y ago
    With most modern PC processors, both GPU and CPU, one of the primary limitations is thermal headroom. There are features and technologies with varying names across brands and processors that essentially do the same thing: run at the maximum clock that the current thermal situation will support. From my personal experience, my Threadripper 3970X will happily maintain ~4.4GHz all-core (rated for 4.5GHz max single-core) so long as I can keep the temperature in or below the 70s, with no overclocking.[0] There are power limits as well, but rated performance numbers are within the power limits. Overclocking can put you past the marked power limits, and certainly needs ample cooling. [0] Granted, I need to pump cold air into the case to maintain the temperature, but that's a limitation of my current thermal solution. At some point I'll probably upgrade to an excessive water cooling solution (:
    - formerly_proven 6y ago
      The difference with watercooling for CPUs seems to mostly come down to lower noise, and only marginally better thermals.
      - greggyb 6y ago
        I can get much more surface area of radiator than can reasonably be reached by the heat pipes on an air cooler. There are limits to how many radiators you can effectively leverage in a cooling loop. Additionally, a loop with a large volume of liquid offers much more thermal buffer before reaching a steady state temperature. Most air coolers will be heat saturated within a minute or so. A water cooling loop may maintain lower temperature for minutes to tens of minutes. So even with two solutions that otherwise reach the same steady state temperatures (and therefore throttle equally), you may see better real world performance out of the water cooling solution. I'll note, I would be building an open loop, not using an AIO/closed loop cooler. My case has room for 7x140mm of radiator in a couple of configurations. I would probably use 5x of that in one 420mm radiator and a 280mm radiator. This should offer much more cooling capacity than any tower cooler.
      - paranoidrobot 6y ago
        I can only offer anecdata, but I built a Ryzen 3600 based desktop earlier in the year. Initially I used the stock cooler, but it idled at ~45C, and the moment I did anything approaching a load it immediately shot to 90C. This was in a room with ambient at around 23C. After getting annoyed for a while I swapped for an AIO Liquid cooler and hey-presto it now idles at 30C and when maxed out - 75C.
        jrockway 6y ago
        That is all OK, but remember that Zen 2 really tries hard to hit 90C. Especially if you go into Ryzen Master and turn on Automatic Overclocking (very conservative overclocking by enthusiast standards), and your motherboard doesn't have power delivery limitations, the CPU's main goal is to try to hit 90C under load. It will automatically adjust frequency and core voltage up until it hits a thermal limit; by taking more heat away from the CPU with better cooling, you end up with better performance because the CPU will try to automatically give you the best performance that your thermal solution can deliver. AMD didn't document any of this very well (lots of confusion between Precision Boost 2 and Precision Boost Overdrive), but the technology is very impressive. I guess what I'm saying is that you might be interested in exploring some of these options in Ryzen Master. You have some thermal headroom, so if your motherboard has good power delivery, you can max out the power limits and boost clock limits, and probably squeeze out a little extra performance. Power (and therefore heat) is going to scale quadratically with core voltage, and frequency is going to scale less than linearly with voltage, so you might not see much gain (and might prefer not spinning your fans up to full speed under load). But, it's an option that's available if that sort of thing interests you. I got about 6% more real-world speed out of my Threadripper 3970X by switching from OC off to Automatic Overclocking; with air cooling. AMD's technology here is pretty impressive.
- MrRadar 6y ago
  > Historically, clock speeds scaled inversely with the # of cores. It's the miracle of chiplets. AMD isn't binning one 16-core CPU, they're binning two 8-core CPUs and then combining them together.
GuB-42 6y ago
Maybe not the voodoo you are thinking about but on the GPU side, the 3Dfx Voodoo was indeed a groundbreaking 3D accelerator card. At the time, 3Dfx main competitors were Nvidia and ATI, Nvidia finally bought 3Dfx and AMD bought ATI. So technically, voodoo is on the side of AMD's competition.
- greggyb 6y ago
  Intel's name for its CPU architecture is "Core." Nevertheless, AMD discusses its CPU cores. "voodoo" and "Voodoo" need not be the same (;
  - pepoluan 6y ago
    Should have named their CPU Architecture the "Crore" instead ;-)
zanny 6y ago
TDP is about as meaningful on CPUs now as nm is in fab tech. In practice the 3950x pulled up to ~225w running maxxed out avx2 workloads, ~300w if you overclocked it. The 3900x pulls up to ~190 watts at stock boosts. Both are called "105w TDP" parts.
- greggyb 6y ago
  If you're going to attack the "spec" that is TDP, you may as well do it correctly. None of the scenarios you mentioned align with what TDP is supposed to "measure". Even if TDP weren't the flawed measure it is, you still wouldn't be critiquing it by noting the measures you have. Here's the critique you should use! https://www.gamersnexus.net/guides/3525-amd-ryzen-tdp-explained-deep-dive-cooler-manufacturer-opinions https://www.gamersnexus.net/guides/3525-amd-ryzen-tdp-explai... Nevertheless, for a given manufacturer, TDP is useful as a coarse grouping of power consumption.
  - Dylan16807 6y ago
    I disagree. If TDP wasn't so flawed as to be completely meaningless, that critique would probably be valid. The definition AMD uses is absolute nonsense, given how much the θca values differ from model to model. If they fudged any harder the higher end CPUs would start having "TDP" lower than the weak CPUs.
- NorwegianDude 6y ago
  PPT on the 105W TDP CPUs are ~143W by default, so your numbers are way of and not possible without overclocking by removing the limit. You'll also go way beyond 300W with heavy overclocking.
- juergbi 6y ago
  This is incorrect, to the best of my knowledge. 3900X and 3950X both have a 142W package power limit (PPT, 35% above TDP) at stock, with a properly working motherboard. As I understand it, not even short boosts are allowed to use more power than the PPT. The limit can be lifted in the BIOS (or e.g. Ryzen Master) but that would no longer be stock operation. And there was a defect in the initial BIOS of ASRock X570 and maybe other motherboards, which broke PPT but that was running the CPU out of spec, not stock operation.

That 5950X (and its predecessor) seem like voodoo with the core count, clock frequency, and TDP (yes, I know TDP is a flawed, flawed number - it's still impressive).

bob1029 6y ago

I second this reaction. Historically, clock speeds scaled inversely with the # of cores. Seems like the efficiency is overtaking other constraints at this point.

deleted 6y ago
[deleted]
loeg 6y ago
The achievable all-core clock will inevitably scale inversely with # of cores, in practice. The advertised single core and all-core clocks are some combination of binning and pure marketing.
- greggyb 6y ago
  With most modern PC processors, both GPU and CPU, one of the primary limitations is thermal headroom. There are features and technologies with varying names across brands and processors that essentially do the same thing: run at the maximum clock that the current thermal situation will support. From my personal experience, my Threadripper 3970X will happily maintain ~4.4GHz all-core (rated for 4.5GHz max single-core) so long as I can keep the temperature in or below the 70s, with no overclocking.[0] There are power limits as well, but rated performance numbers are within the power limits. Overclocking can put you past the marked power limits, and certainly needs ample cooling. [0] Granted, I need to pump cold air into the case to maintain the temperature, but that's a limitation of my current thermal solution. At some point I'll probably upgrade to an excessive water cooling solution (:
  - formerly_proven 6y ago
    The difference with watercooling for CPUs seems to mostly come down to lower noise, and only marginally better thermals.
    - greggyb 6y ago
      I can get much more surface area of radiator than can reasonably be reached by the heat pipes on an air cooler. There are limits to how many radiators you can effectively leverage in a cooling loop. Additionally, a loop with a large volume of liquid offers much more thermal buffer before reaching a steady state temperature. Most air coolers will be heat saturated within a minute or so. A water cooling loop may maintain lower temperature for minutes to tens of minutes. So even with two solutions that otherwise reach the same steady state temperatures (and therefore throttle equally), you may see better real world performance out of the water cooling solution. I'll note, I would be building an open loop, not using an AIO/closed loop cooler. My case has room for 7x140mm of radiator in a couple of configurations. I would probably use 5x of that in one 420mm radiator and a 280mm radiator. This should offer much more cooling capacity than any tower cooler.
    - paranoidrobot 6y ago
      I can only offer anecdata, but I built a Ryzen 3600 based desktop earlier in the year. Initially I used the stock cooler, but it idled at ~45C, and the moment I did anything approaching a load it immediately shot to 90C. This was in a room with ambient at around 23C. After getting annoyed for a while I swapped for an AIO Liquid cooler and hey-presto it now idles at 30C and when maxed out - 75C.
      - jrockway 6y ago
        That is all OK, but remember that Zen 2 really tries hard to hit 90C. Especially if you go into Ryzen Master and turn on Automatic Overclocking (very conservative overclocking by enthusiast standards), and your motherboard doesn't have power delivery limitations, the CPU's main goal is to try to hit 90C under load. It will automatically adjust frequency and core voltage up until it hits a thermal limit; by taking more heat away from the CPU with better cooling, you end up with better performance because the CPU will try to automatically give you the best performance that your thermal solution can deliver. AMD didn't document any of this very well (lots of confusion between Precision Boost 2 and Precision Boost Overdrive), but the technology is very impressive. I guess what I'm saying is that you might be interested in exploring some of these options in Ryzen Master. You have some thermal headroom, so if your motherboard has good power delivery, you can max out the power limits and boost clock limits, and probably squeeze out a little extra performance. Power (and therefore heat) is going to scale quadratically with core voltage, and frequency is going to scale less than linearly with voltage, so you might not see much gain (and might prefer not spinning your fans up to full speed under load). But, it's an option that's available if that sort of thing interests you. I got about 6% more real-world speed out of my Threadripper 3970X by switching from OC off to Automatic Overclocking; with air cooling. AMD's technology here is pretty impressive.
MrRadar 6y ago
> Historically, clock speeds scaled inversely with the # of cores. It's the miracle of chiplets. AMD isn't binning one 16-core CPU, they're binning two 8-core CPUs and then combining them together.

GuB-42 6y ago

Maybe not the voodoo you are thinking about but on the GPU side, the 3Dfx Voodoo was indeed a groundbreaking 3D accelerator card. At the time, 3Dfx main competitors were Nvidia and ATI, Nvidia finally bought 3Dfx and AMD bought ATI. So technically, voodoo is on the side of AMD's competition.

greggyb 6y ago
Intel's name for its CPU architecture is "Core." Nevertheless, AMD discusses its CPU cores. "voodoo" and "Voodoo" need not be the same (;
- pepoluan 6y ago
  Should have named their CPU Architecture the "Crore" instead ;-)

zanny 6y ago

TDP is about as meaningful on CPUs now as nm is in fab tech. In practice the 3950x pulled up to ~225w running maxxed out avx2 workloads, ~300w if you overclocked it. The 3900x pulls up to ~190 watts at stock boosts. Both are called "105w TDP" parts.

greggyb 6y ago
If you're going to attack the "spec" that is TDP, you may as well do it correctly. None of the scenarios you mentioned align with what TDP is supposed to "measure". Even if TDP weren't the flawed measure it is, you still wouldn't be critiquing it by noting the measures you have. Here's the critique you should use! https://www.gamersnexus.net/guides/3525-amd-ryzen-tdp-explained-deep-dive-cooler-manufacturer-opinions https://www.gamersnexus.net/guides/3525-amd-ryzen-tdp-explai... Nevertheless, for a given manufacturer, TDP is useful as a coarse grouping of power consumption.
- Dylan16807 6y ago
  I disagree. If TDP wasn't so flawed as to be completely meaningless, that critique would probably be valid. The definition AMD uses is absolute nonsense, given how much the θca values differ from model to model. If they fudged any harder the higher end CPUs would start having "TDP" lower than the weak CPUs.
NorwegianDude 6y ago
PPT on the 105W TDP CPUs are ~143W by default, so your numbers are way of and not possible without overclocking by removing the limit. You'll also go way beyond 300W with heavy overclocking.
juergbi 6y ago
This is incorrect, to the best of my knowledge. 3900X and 3950X both have a 142W package power limit (PPT, 35% above TDP) at stock, with a properly working motherboard. As I understand it, not even short boosts are allowed to use more power than the PPT. The limit can be lifted in the BIOS (or e.g. Ryzen Master) but that would no longer be stock operation. And there was a defect in the initial BIOS of ASRock X570 and maybe other motherboards, which broke PPT but that was running the CPU out of spec, not stock operation.