Is the GPU in Intel Kaby Lake-G More Polaris than Vega?
Subject: Graphics Cards, Processors | April 9, 2018 - 04:25 PM | Ryan Shrout
Tagged: Vega, Polaris, kaby lake-g, Intel, amd
Over the weekend, some interesting information has surfaced surrounding the new Kaby Lake-G hardware from Intel. A product that is officially called the “8th Generation Intel Core Processors with Radeon RX Vega M Graphics” is now looking like it might be more of a Polaris-based GPU than a Vega-based one. This creates an interesting marketing and technology capability discussion for the community, and both Intel and AMD, that is worth diving into.
PCWorld first posted the question this weekend, using some interesting data points as backup that Kaby Lake-G may in fact be based on Polaris. In Gordon’s story he notes that in AIDA64 the GPU is identified as “Polaris 22” while the Raven Ridge-based APUs from AMD show up as “Raven Ridge.” Obviously the device identification of a third party piece of software is a suspect credential in any situation, but the second point provided is more salient: based on the DXDiag information, the GPU on the Hades Canyon NUC powered by Kaby Lake-G does not support DirectX 12.1.
Image source: PCWorld
AMD clearly stated in its launch of the Vega architecture last year that the new GPUs supported DX 12.1, among other features. The fact that the KBL-G part does NOT include support for it is compelling evidence that the GPU might be more similar to Polaris than Vega.
Tom’s Hardware did some more digging that was posted this morning, using a SiSoft Sandra test that can measure performance of FP16 math and FP32. For both the Radeon RX Vega 64 and 56 discrete graphics cards, running the test with FP16 math results in a score that is 65% faster than the FP32 results. With a Polaris-based graphics card, an RX 470, the scores between FP32 and FP16 were identical as the architecture can support FP16 math functions but doesn’t accelerate it with AMD’s “rapid packed math” feature (that was a part of the Vega launch).
Image source: Tom's Hardware
And you guessed it, the Kaby Lake-G part only runs essentially even in the FP16 mode. (Also note that AMD’s Raven Ridge APU that integrated Vega graphics does get accelerated by 61% using FP16.)
What Kaby Lake-G does have that leans toward Vega is support for HBM2 memory (which none of the Polaris cards have) and “high bandwidth memory cache controller and enhanced compute units with additional ROPs” according to the statement from Intel given to Tom’s Hardware.
It should be noted that just because the benchmarks and games that can support rapid packed math don’t take advantage of that capability today, does not mean they won’t have the capability to do so after a driver or firmware update. That being said, if that’s the plan, and even if it’s not, Intel should come out and tell the consumers and media.
The debate and accusations of conspiracy are running rampant again today with this news. Is Intel trying to pull one over on us by telling the community that this is a Vega-based product when it is in fact based on Polaris? Why would AMD allow and promote the Vega branding with a part that it knows didn’t meet the standards it created to be called a Vega architecture solution?
Another interesting thought comes when analyzing this debate with the Ryzen 7 2400G and Ryzen 5 2200G products, both of which claim to use Vega GPUs as a portion of the APU. However, without support for HBM2 or the high-bandwidth cache controller, does that somehow shortchange the branding for it? Or are the memory features of the GPU considered secondary to its design?
This is the very reason why companies hate labels, hate specifications, and hate having all of this tracked by a competent and technical media. Basically every company in the tech industry is guilty of this practice: Intel has 2-3 architectures running as “8th Generation” in the market, AMD is selling RX 500 cards that were once RX 400 cards, and NVIDIA has changed performance capabilities of the MX 150 at least once or twice.
The nature of semi-custom chips designs is that they are custom. Are the GPUs used in the PS4 and Xbox One or Xbox One X called Polaris, Vega, or something else? It would be safer for AMD and its partners to give each new product its own name, its own brand—but then the enthusiasts would want to know what it was most like, and how did it compare to Polaris, or Vega, etc.? It’s also possible that AMD was only willing to sell this product to Intel if it included some of these feature restrictions. In complicated negotiations like this one surely was, anything is feasible.
These are tough choices for companies to make. AMD loves having the Vega branding in more products as it gives weight to the development cost and time it spent on the design. Having Vega associated with more high-end consumer products, including those sold by Intel, give them leverage for other products down the road. From Intel’s vantage point using the Vega brand makes it looks like it has the very latest technology in its new processor and it can benefit from any cross-promotion that occurs around the Vega brand from AMD or its partners.
Unfortunately, it means that the devil is in the details, and the details are something that no one appears to be willing to share. Does it change the performance we saw in our recent Hades Canyon NUC review or our perspective on it as a product? It does not. But as features like Rapid Packed Math or the new geometry shader accelerate in adoption, the capability for Kaby Lake-G to utilize them is going to be scrutinized more heavily.