5 ms·

Microbenchmarking AMD’s RDNA 3 Graphics Architecture

85 points by zdw 4y ago

tw1984 4y ago
this chipsandcheese.com web site seems like a gold mine to me - I am visiting HN every few hours for exact such hard core tech stuff! more please! thanks for sharing the info/link!
- hajile 4y ago
  It really is a kind of spiritual successor to Real World Tech and Anandtech. The number of enthusiasts is at an all time high, but the number of in depth tech articles seems to be at an all time low. Everything is just high traffic cursory reviews that often border on clickbait.
  - paulmd 4y ago
    There is no money in written content anymore, and it's very difficult to deliver this kind of content as a video. Even for the people who try, it ends up being very lengthy 40m or 90m videos that could really have been a couple pages of text. Leaving the content completely aside, the future of content production is MLID-style stuff, he's been very successful at commercializing his work via the patron model. Some focus videos, some weekly news videos, some viewer "call-in" (chat, discord, etc) interaction videos. You can see Ian Cutress and others moving towards this somewhat. Greg's Airplanes and Automobiles (where my greggheads at?) is one of the few who I'd say produces content that is comparable to long-form written content, and honestly he suffers from the bloat problem. His series on the P-47 is eight parts and none of the parts is less than 40 minutes a video, several are almost 90 minutes. And I doubt he makes anywhere near as much as the more "interactive" and broad/shallow content channels from that ten hours of content. And there's probably another 10-20 hours of research behind every hour of content... which is much lower for shallow content as well. And there is zero chance that written content would make even as much as Greg makes. People aren't willing to pay for it. That's why written tech media (and deep dives) is dying and you get 30 minute GN reviews instead of a 3 page article. I guess what I'm saying is click that donate button on Chips+Cheese's site. Not that I'm any better about it.
deleted 4y ago
[deleted]
raphlinus 4y ago
I really enjoyed this. I use a 5700 XT (RDNA 2) as my one of my main development GPUs, and appreciate its particular strengths, and because of this article am quite tempted to get an RDNA 3 card. A few observations. First, the astonishingly low latency for LDS (aka workgroup shared memory). Vello uses this fairly extensively (especially in prefix sum / monoid scan operations, plus the stack monoid), so I'd expect performance to be quite sweet on this card. If every card had this, I'm not sure there'd still be a motivation to do subgroups. I also really liked the chart comparing shared memory latency across cards - I already knew that Intel was slow (especially Gen9 and earlier), so it was nice to see quantitative data. Second, it seems really odd to me that there's chip area for dual-issue ALU, giving over 60 TFLOPS of f32, but the shader compiler only achieves single issue most of the time. I wonder if there are plans to improve performance over time through software updates. I'd also be really curious whether using Vulkan subgroup size control would help unlock this higher performance. With that feature, the application can query what subgroup sizes are available (32 and 64 here) and explicitly choose one. I'm really glad this kind of microbenchmarking is being done, we need more of it.
- thomastjeffery 4y ago
  > Vello uses this fairly extensively What is Vello? I'm guessing you mean this: https://github.com/linebender/vello https://github.com/linebender/vello
  - raphlinus 4y ago
    Yes, that's the correct link. For those not following closely, it used to be piet-gpu, but we changed the name since it's not based on the Piet API any more, and the new WGSL shaders are basically a rewrite.
- begvfwedc 4y ago
  nitpick: the 5700 XT is RDNA 1, not RDNA 2.
  - raphlinus 4y ago
JonChesterfield 4y ago
> That makes it possible for the LDS to service a wavefront-wide load every cycle. Well that's awesome. Learned a new thing.
binarymax 4y ago
I’d love to see a ROCm vs CUDA comparison on training some pytorch models of different architectures. The AMD RX 7900 XTX is less than half the price of the NVidia RTX 4090 ($999 vs $2300) EDIT - correction, the MSRP for the 4090 is only $1600
- wtallis 4y ago
  It's totally fair to ignore MSRP and look at only the real prices that you can currently obtain those cards for. Among sellers that actually have stock right now, the RTX 4090 starts a little over $2000 and the 7900 XTX starts around $1200.
- kllrnohj 4y ago
  Take Nvidia's MSRP with a grain of salt. Unless there's a founders edition card on the market, the number can be complete fantasy instead of mostly fantasy (eg, 4070 Ti MSRP is $800 but those cards don't really exist, they all start at $850+). Right now Nvidia is playing a game where the MSRP cards can't be sold at a profit, so you'll only see a token amount of them exist before going out of stock to never return. Hence why even the 4080, which by all accounts has barely sold at all, still has a bunch of out of stock SKUs - coincidentally all the ones that are "MSRP." Realistically the 4090 then also is more like a $1800 card.
  - convery 4y ago
    I remember articles on the 3000 series where manufacturers were reporting that Nvidia was selling the chips themselves at higher price than the MSRP for the entire card. So ye, take that with a scoop of salt =P
    - paulmd 4y ago
      lol, it was one interview from a CEO who was mad that he had to clearance-price 3090s after the mining boom ended, and even GN told you they thought it was dubious and needed to be taken with a bunch of salt. Igor’s Lab says their partner contacts said 2021 was a “10x year” for them, and that’s easily confirmable for at least one partner with public financials data. https://www.wsj.com/market-data/quotes/TW/ROCO/6150/financials https://www.wsj.com/market-data/quotes/TW/ROCO/6150/financia... https://www.igorslab.de/en/evga-pulls-the-plug-with-loud-bang-yet-it-has-long-been-editorial/ https://www.igorslab.de/en/evga-pulls-the-plug-with-loud-ban... Some people really do be seeing EVGA selling a 2080 Ti for $949 and Zotac for $999 and then argue the other partners magically can’t afford to sell for less than $1400. Or think that anything has changed since then. We call them… gamers. It’s honestly crazy to see techies embracing the digital-car-dealership model over the Tesla model. You really really want to fight against scalper-bots instead of just putting in an order on Steam for a 3060 Ti at MSRP and having it come in a month or two? And then everyone acts like rma is only possible with partners… bruh I can rma a cpu to AMD or Intel just fine without a middleman involved. Unironically you are buying into smoothtalk from brylcreemed CEOs who were scalping 3080s in their first-party webstores for triple MSRP and even scalping directly to Ebay (lol MSI) literally weeks before their media tour, they came crying directly after prices crashed as part of a media push to get NVIDIA to refund their excess mining orders. Gamers are the most credulous rubes on the planet, NVIDIA and EVGA can agree on that much. https://www.reddit.com/r/hardware/comments/j6idky/msi_scalping_their_own_3080s_on_ebay_links/ https://www.reddit.com/r/hardware/comments/j6idky/msi_scalpi... and conversely - partners love what NVIDIA is doing with the 30-series price fixing right now! Their margins on 30-series are great, they're not losing money on deep discounts like they are with RDNA2 products. That's not good for consumers, but hey, somehow they've convinced consumers they're on their side instead of a middleman with their hand out. Again, as you can see from the 2080 Ti example, MSRP isn't "losing money" territory, in fact they can probably even go a bit under MSRP (EVGA knocked another 5% off), they just don't like it, at 5% under MSRP EVGA was probably running actual zero margin. It's when prices go 30-50% under MSRP that they lose money. And NVIDIA is doing a great job with 30-series keeping prices at or above MSRPs and making sure nobody breaks ranks and cuts prices. Trusts are super effective at maintaining margins, and consumers love making sure partners get their margins, right?

85 points by zdw 4y ago

tw1984 4y ago

this chipsandcheese.com web site seems like a gold mine to me - I am visiting HN every few hours for exact such hard core tech stuff! more please! thanks for sharing the info/link!

hajile 4y ago
It really is a kind of spiritual successor to Real World Tech and Anandtech. The number of enthusiasts is at an all time high, but the number of in depth tech articles seems to be at an all time low. Everything is just high traffic cursory reviews that often border on clickbait.
- paulmd 4y ago
  There is no money in written content anymore, and it's very difficult to deliver this kind of content as a video. Even for the people who try, it ends up being very lengthy 40m or 90m videos that could really have been a couple pages of text. Leaving the content completely aside, the future of content production is MLID-style stuff, he's been very successful at commercializing his work via the patron model. Some focus videos, some weekly news videos, some viewer "call-in" (chat, discord, etc) interaction videos. You can see Ian Cutress and others moving towards this somewhat. Greg's Airplanes and Automobiles (where my greggheads at?) is one of the few who I'd say produces content that is comparable to long-form written content, and honestly he suffers from the bloat problem. His series on the P-47 is eight parts and none of the parts is less than 40 minutes a video, several are almost 90 minutes. And I doubt he makes anywhere near as much as the more "interactive" and broad/shallow content channels from that ten hours of content. And there's probably another 10-20 hours of research behind every hour of content... which is much lower for shallow content as well. And there is zero chance that written content would make even as much as Greg makes. People aren't willing to pay for it. That's why written tech media (and deep dives) is dying and you get 30 minute GN reviews instead of a 3 page article. I guess what I'm saying is click that donate button on Chips+Cheese's site. Not that I'm any better about it.

deleted 4y ago

[deleted]

raphlinus 4y ago

I really enjoyed this. I use a 5700 XT (RDNA 2) as my one of my main development GPUs, and appreciate its particular strengths, and because of this article am quite tempted to get an RDNA 3 card. A few observations. First, the astonishingly low latency for LDS (aka workgroup shared memory). Vello uses this fairly extensively (especially in prefix sum / monoid scan operations, plus the stack monoid), so I'd expect performance to be quite sweet on this card. If every card had this, I'm not sure there'd still be a motivation to do subgroups. I also really liked the chart comparing shared memory latency across cards - I already knew that Intel was slow (especially Gen9 and earlier), so it was nice to see quantitative data. Second, it seems really odd to me that there's chip area for dual-issue ALU, giving over 60 TFLOPS of f32, but the shader compiler only achieves single issue most of the time. I wonder if there are plans to improve performance over time through software updates. I'd also be really curious whether using Vulkan subgroup size control would help unlock this higher performance. With that feature, the application can query what subgroup sizes are available (32 and 64 here) and explicitly choose one. I'm really glad this kind of microbenchmarking is being done, we need more of it.

thomastjeffery 4y ago
> Vello uses this fairly extensively What is Vello? I'm guessing you mean this: https://github.com/linebender/vello https://github.com/linebender/vello
- raphlinus 4y ago
  Yes, that's the correct link. For those not following closely, it used to be piet-gpu, but we changed the name since it's not based on the Piet API any more, and the new WGSL shaders are basically a rewrite.
begvfwedc 4y ago
nitpick: the 5700 XT is RDNA 1, not RDNA 2.
- raphlinus 4y ago

JonChesterfield 4y ago

> That makes it possible for the LDS to service a wavefront-wide load every cycle. Well that's awesome. Learned a new thing.

binarymax 4y ago

I’d love to see a ROCm vs CUDA comparison on training some pytorch models of different architectures. The AMD RX 7900 XTX is less than half the price of the NVidia RTX 4090 ($999 vs $2300) EDIT - correction, the MSRP for the 4090 is only $1600

wtallis 4y ago
It's totally fair to ignore MSRP and look at only the real prices that you can currently obtain those cards for. Among sellers that actually have stock right now, the RTX 4090 starts a little over $2000 and the 7900 XTX starts around $1200.
kllrnohj 4y ago
Take Nvidia's MSRP with a grain of salt. Unless there's a founders edition card on the market, the number can be complete fantasy instead of mostly fantasy (eg, 4070 Ti MSRP is $800 but those cards don't really exist, they all start at $850+). Right now Nvidia is playing a game where the MSRP cards can't be sold at a profit, so you'll only see a token amount of them exist before going out of stock to never return. Hence why even the 4080, which by all accounts has barely sold at all, still has a bunch of out of stock SKUs - coincidentally all the ones that are "MSRP." Realistically the 4090 then also is more like a $1800 card.
- convery 4y ago
  I remember articles on the 3000 series where manufacturers were reporting that Nvidia was selling the chips themselves at higher price than the MSRP for the entire card. So ye, take that with a scoop of salt =P
  - paulmd 4y ago
    lol, it was one interview from a CEO who was mad that he had to clearance-price 3090s after the mining boom ended, and even GN told you they thought it was dubious and needed to be taken with a bunch of salt. Igor’s Lab says their partner contacts said 2021 was a “10x year” for them, and that’s easily confirmable for at least one partner with public financials data. https://www.wsj.com/market-data/quotes/TW/ROCO/6150/financials https://www.wsj.com/market-data/quotes/TW/ROCO/6150/financia... https://www.igorslab.de/en/evga-pulls-the-plug-with-loud-bang-yet-it-has-long-been-editorial/ https://www.igorslab.de/en/evga-pulls-the-plug-with-loud-ban... Some people really do be seeing EVGA selling a 2080 Ti for $949 and Zotac for $999 and then argue the other partners magically can’t afford to sell for less than $1400. Or think that anything has changed since then. We call them… gamers. It’s honestly crazy to see techies embracing the digital-car-dealership model over the Tesla model. You really really want to fight against scalper-bots instead of just putting in an order on Steam for a 3060 Ti at MSRP and having it come in a month or two? And then everyone acts like rma is only possible with partners… bruh I can rma a cpu to AMD or Intel just fine without a middleman involved. Unironically you are buying into smoothtalk from brylcreemed CEOs who were scalping 3080s in their first-party webstores for triple MSRP and even scalping directly to Ebay (lol MSI) literally weeks before their media tour, they came crying directly after prices crashed as part of a media push to get NVIDIA to refund their excess mining orders. Gamers are the most credulous rubes on the planet, NVIDIA and EVGA can agree on that much. https://www.reddit.com/r/hardware/comments/j6idky/msi_scalping_their_own_3080s_on_ebay_links/ https://www.reddit.com/r/hardware/comments/j6idky/msi_scalpi... and conversely - partners love what NVIDIA is doing with the 30-series price fixing right now! Their margins on 30-series are great, they're not losing money on deep discounts like they are with RDNA2 products. That's not good for consumers, but hey, somehow they've convinced consumers they're on their side instead of a middleman with their hand out. Again, as you can see from the 2080 Ti example, MSRP isn't "losing money" territory, in fact they can probably even go a bit under MSRP (EVGA knocked another 5% off), they just don't like it, at 5% under MSRP EVGA was probably running actual zero margin. It's when prices go 30-50% under MSRP that they lose money. And NVIDIA is doing a great job with 30-series keeping prices at or above MSRPs and making sure nobody breaks ranks and cuts prices. Trusts are super effective at maintaining margins, and consumers love making sure partners get their margins, right?