Spitballing the performance of AMD’s Radeon Vega Frontier Edition graphics card
AMD's Radeon Vega Frontier Edition reveal yesterday provided us with some important pieces of the performance puzzle for one of the most hotly-anticipated graphics chips of 2017. Crucially, AMD disclosed the Frontier Edition card's pixel fill rate and some rough expectations for floating-point throughput—figures that allow us to make some educated guesses about Vega's final clock speeds and how it might stack up to Nvidia's latest and greatest for both gaming and compute performance.
Dollars and sense
Before we dive into my educated guesses, though, it's worth mulling over the fact that the Vega Frontier Edition is launching as a Radeon Pro card, not a Radeon RX card. As Ryan Smith at Anandtech points out, this is the first time AMD is debuting a new graphics architecture aboard a professional-grade product. As its slightly green-tinged name suggests, AMD's Frontier Edition strategy roughly echoes how Nvidia has been releasing new graphics architectures of late. Pascal made its debut aboard the Tesla P100 accelerator, and the market's first taste of Nvidia's Volta architecture will be aboard a similar product.
These developments suggest that whether they bleed red or green, gamers may have to accept the fact that they aren't the most important market for these high-performance, next-gen graphics chips any longer.
Though gamers might feel disappointed after yesterday's reveal, this decision makes good business sense. As I mused about on Twitter a few days ago, it doesn't make any sense for the company to sell Vega chips on Radeon RX cards just yet when there's strong demand for this GPU's compute power elsewhere. In turn, AMD can ask much more money for Vega compute accelerators than it can for the same chip aboard a Radeon gaming card. Yesterday's Financial Analyst Day made it clear that AMD is acutely aware of the high demand for GPU compute power right now, especially for machine learning applications, and it wants as big a piece of that pie as it can grab.
Radeon Technologies Group head Raja Koduri put some numbers to this idea at the company's analyst day by pointing out that the high end of the graphics card market could represent less than 15% of the company's sales volume, but potentially as much as 66% of its margin contribution (i.e., profit). Nvidia dominates the high-end graphics card market regardless of whether one is running workstation graphics or datacenter GPU computing tasks, and AMD needs to tap into the demand from these markets as part of its course toward profitability. Radeon RX products might make the most noise in the consumer graphics market, but Vega compute cards could make the biggest bucks for AMD, so it only makes sense that the company is launching the Frontier Edition (and presumably the Radeon Instinct MI25) into the very highest end of the market first.
Sizing up Vega
Now, let's talk some numbers. AMD says the Vega GPU aboard the Frontier Edition will offer about 13 TFLOPS of FP32 and about 25 TFLOPS of FP16 performance, as well as a pixel fill rate of 90 Gpixels/s. AMD also says the chip will have 64 compute units and 4096 stream processors, and that FP32 TFLOPS figure suggests a clock speed range of about 1450 MHz to 1600 MHz. I propose this range because AMD seems to have used different clock rates to calculate different peak throughput rates. I'm also guessing the Vega chip in this card also has 64 ROPs, given the past layout of GCN cards and the way the numbers have to stack up to reach that 90 Gpixels/s figure.
|GTX 970||1050||1178||56||104||1664||224+32||224 GB/s||3.5+0.5GB||145W|
|GTX 980||1126||1216||64||128||2048||256||224 GB/s||4 GB||165W|
|GTX 980 Ti||1002||1075||96||176||2816||384||336 GB/s||6 GB||250W|
|Titan X (Maxwell)||1002||1075||96||192||3072||384||336 GB/s||12 GB||250W|
|GTX 1080||1607||1733||64||160||2560||256||320 GB/s||8GB||180W|
|GTX 1080 Ti||1480||1582||88||224||3584||352||484 GB/s||11GB||250W|
|Titan Xp||1480?||1582||96||240||3840||384||547 GB/s||12GB||250W|
|R9 Fury X||—||1050||64||256||4096||1024||512 GB/s||4GB||275W|
|Vega Frontier Edition||~1450?||~1600?||64?||256?||4096||???||~480 GB/s||16GB||???|
Regardless, that clock-speed range and the resulting numbers suggest that AMD will meet or exceed its compute performance targets for its first Vega products. The company touted a 25 TFLOPS rate for FP16 math when it previewed the Radeon Instinct MI25 card, and the Vega Frontier Edition could potentially top that already-impressive figure with 26 TFLOPS or so at the top of its hypothetical clock range. Assuming those numbers hold, the raw compute capabilities of the Vega FE for some types of math will top even the beastly Quadro GP100, Nvidia's highest-end pro graphics card at the moment. These are both high-end pro cards with 16GB of HBM2 on board, so it's not far-fetched to compare them.
|Asus R9 290X||67||185/92||4.2||5.9|
|Radeon R9 295 X2||130||358/179||8.1||11.3|
|Radeon R9 Fury X||67||269/134||4.2||8.6|
|GeForce GTX 780 Ti||37||223/223||4.6||5.3|
|Gigabyte GTX 980 Windforce||85||170/170||5.3||5.4|
|GeForce GTX 980 Ti||95||189/189||6.5||6.1|
|GeForce GTX 1070||108||202/202||5.0||7.0|
|GeForce GTX 1080||111||277/277||6.9||8.9|
|GeForce GTX 1080 Ti||139||354/354||9.5||11.3|
|GeForce Titan Xp||152||343/343||9.2||11.0|
|Vega Frontier Edition||~90-102?||410?/205?||6.4?||13.0|
Taking AMD's squishy numbers at face value, the 25 TFLOPS of FP16 the Vega FE claims to offer will top the Quadro GP100's claimed 20.7 TFLOPS of FP16 throughput. In turn, AMD claims the Vega FE can deliver about 26% higher FP32 throughput than the Quadro GP100: 13 TFLOPS versus 10.3 TFLOPS. The GP100 might deliver higher double-precision math rates, but we can't compare the Vega FE card's performance on that point because AMD hasn't said a word about Vega's FP64 capability. Even so, the $8900 price tag of the Quadro GP100 gives AMD plenty of wiggle room to field a competitor in this lucrative market, and it seems the performance will be there to make Vega a worthy compute competitor (at least until Volta descends from the data center).
The things we still don't know about the Vega chip in the Frontier Edition are facts most relevant to the chip's gaming performance. AMD hasn't talked in depth about the texturing capabilities or geometry throughput of the Vega architecture yet, but it's simply too tantalizing not to guess at how this Vega chip will stack up given its seeming family resemblance to Fiji cards. Beware: wild guesses ahead.
Assuming Vega maintains 256 texture units and GCN's half-rate throughput for FP16 textures (and this is a big if), the card might deliver as much as 410 GTex/s for int8 textures and 205 GTex/s for bilinear fp16 filtering. For comparison, the GTX 1080 can deliver full throughput for both types of texturing. Even so, that card tops out at 277 GTex/s for both int8 and fp16 work. The Vega FE's impressive texture-crunching capabilites might be slightly tempered by that 90 GPix/s fill rate, which slightly trails even the GTX 1070's theoretical capabilities.
Either way, none of these dart throws suggest the eventual RX Vega will have what it takes to unseat the GeForce GTX 1080 Ti atop the consumer graphics-performance race, as some wild rumors have postulated recently. I'm willing to be surprised, though. We also can't account for the potential performance improvements from Vega's new primitive shader support or its tile-based Draw Stream Binning Rasterizer, both of which could mitigate some of these theoretical shortcomings somewhat.
All of those guesses square pretty nicely with my seat-of-the-pants impressions of Vega's gaming power during AMD's demo sessions, where the card delivered performance that felt like it was in the ballpark with a GeForce GTX 1080. I gleaned those impressions from AMD demo darling Doom, of course, and other games will perform differently. It's also possible that the Radeon RX Vega will use a different configuration of the Vega GPU, so AMD Vega FE numbers may not be the best starting point. Still, if it's priced right, the Radeon RX Vega could be the high-end gaming contender that AMD sorely needs. We'll have to see whether my guesses are on the mark or wide of the mark when Radeon RX Vega cards finally appear.
This article initially speculated, without sourcing, that AMD would include 4096 SPs on the Vega FE GPU. The company did, in fact, confirm that the Vega GPU on this card would include 4096 SPs on a separate product page that I overlooked. While this new information does not affect any of the guesses put forth in this piece, I do regret the error, and the piece has been updated to include numbers from AMD's official specs.