[HN Gopher] Microbenchmarking AMD's RDNA 3 Graphics Architecture
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Microbenchmarking AMD's RDNA 3 Graphics Architecture
Author : zdw
Score : 76 points
Date : 2023-01-08 02:23 UTC (20 hours ago)
(HTM) web link (chipsandcheese.com)
(TXT) w3m dump (chipsandcheese.com)
| raphlinus wrote:
| 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 wrote:
| > Vello uses this fairly extensively
|
| What is Vello?
|
| I'm guessing you mean this: https://github.com/linebender/vello
| raphlinus wrote:
| 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.
| JonChesterfield wrote:
| > That makes it possible for the LDS to service a wavefront-wide
| load every cycle.
|
| Well that's awesome. Learned a new thing.
| binarymax wrote:
| 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
| lmedinas wrote:
| Well, as a matter of fact, the 7900 XTX is much closer to the
| RTX 4080 than to the RTX 4090.
| binarymax wrote:
| For deep learning I'm going off the article's benchmark suite
| tests vs the 4090: https://i0.wp.com/chipsandcheese.com/wp-
| content/uploads/2022...
| wtallis wrote:
| 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 wrote:
| 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.
| paulmd wrote:
| > (eg, 4070 Ti MSRP is $800 but those cards don't really
| exist, they all start at $850+).
|
| here's newegg right now:
|
| https://i.imgur.com/al8N35W.png
|
| stop listening to a bunch of rabble-rousing techtubers lol,
| the pitchfork brigade isn't always right.
| kllrnohj wrote:
| Of the 24 4070 Ti cards for sale on Newegg, exactly 2 of
| them are $799.
|
| You're kinda proving the point here while framing it as a
| counter argument lol
| lmedinas wrote:
| The 4090s costs >=4k Euros in Germany right now. So that MSRP
| is completely unrealistic.
|
| Still i think, even with these crazy prices, the price per
| performance increased compared to the previous generation.
| The 4090 is a very good card.
|
| There goes the time of the 700 Euros high end models.
| convery wrote:
| 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 wrote:
| 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/financia...
|
| 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_scalp
| i...
|
| 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?
| kllrnohj wrote:
| > 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.
|
| So.. during a year of highly inflated GPU prices, GPU
| vendors who sold everything far above MSRP made a bunch
| of money?
|
| No shit, Sherlock. What does that have to do with
| Nvidia's well known, well sourced MSRP games?
|
| And since you're so focused on the 30xx series, reminder
| that the MSRP of the 3070 was $500 and even now at the
| end of the product life it's still slim pickings below
| $600. 3080's MSRP was also $700. But again, even now at
| EOL there's very little at that price point. The major
| brands are all $900+
| paulmd wrote:
| What MSRP games? Can you cite some specific claims from
| various sources that aren't just the partner CEO that GN
| said to "take with a bunch of salt" and that Igor
| confirmed doesn't reflect the other partners' margins or
| sentiment?
|
| Again: 2080 Ti is a great example of how those claims
| aren't really true. There was nothing stopping the other
| partners from offering MSRP cards _just like EVGA and
| Zotac_. They could even have gone _under_ MSRP, _just
| like EVGA_.
|
| Partners won't do it because they don't make _enough_
| money, not because they lose money. EVGA and Zotac show
| they 're not losing money doing it, they just don't want
| to.
|
| It's car dealerships whining they're only making 5% on a
| budget car instead of 15% on a corvette.
| [deleted]
| tw1984 wrote:
| 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 wrote:
| 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.
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