AMD Radeon RX 7900 XTX, Radeon 7900 XT, and RDNA 3 Revealed

The AMD RDNA 3 structure has lastly been formally unwrapped, alongside the brand new $999 Radeon RX 7900 XTX and $899 Radeon RX 7900 XT graphics playing cards. These are set to go head-to-head with the finest graphics playing cards, and AMD looks like it may need a official shot on the prime of the GPU benchmarks hierarchy. Right here’s what we all know.

First, a lot of the particulars align with what was already anticipated and lined in our AMD RDNA 3 structure and RX 7000-series GPUs. RDNA 3 will use chiplets, with a important GCD (Graphics Compute Die) and as much as six MCDs (Reminiscence Cache Dies). As well as, there are loads of under-the-hood modifications to the structure, together with extra Compute Models and a lot extra GPU shaders in comparison with the earlier era.

Basically, AMD continues to deal with energy and vitality effectivity and has focused a 50% enchancment in efficiency per watt with RDNA 3 in comparison with RDNA 2. We all know Nvidia’s RTX 4090 and Ada Lovelace pushed far up the voltage and frequency curve, and as we confirmed in our RTX 4090 effectivity scaling, energy limiting the RTX 4090 to 70% vastly boosted Nvidia’s effectivity. Nonetheless, AMD apparently feels no have to dial the ability use as much as 11 at default.

Let’s begin with a fast overview of the core specs, evaluating AMD’s upcoming GPUs with the highest earlier era RDNA 2 and Nvidia’s RTX 4090.

AMD has two variants of the Navi 31 GPU popping out. The upper spec RX 7900 XTX card makes use of the absolutely enabled GCD and 6 MCDs, whereas the RX 7900 XT has 84 of the 96 Compute Models enabled and solely makes use of 5 MCDs. The sixth MCD is technically nonetheless current on the playing cards, nevertheless it’s both a non-functional die or probably even a dummy die. Both method, it is going to be fused off, and it isn’t related to the additional 4GB of GDDR6 reminiscence, so there will not be a solution to re-enable the additional MCD.

In comparison with the competitors, the RX 7900 XTX nonetheless technically is available in behind the RTX 4090 in uncooked compute, and Nvidia has much more AI processing energy with its tensor cores. However we additionally need to keep in mind that the RX 6950 XT managed to maintain up with the RTX 3090 Ti at 1080p and 1440p and was solely about 5% behind at 4K. That is regardless of having theoretically 40% much less uncooked compute. So, when the RX 7900 XTX on paper has 32% much less compute than the RTX 4090, we do not truly know what that can imply in the true world of efficiency benchmarks.

Additionally, word that AMD’s presentation says 61 teraflops whereas our determine is 56.5 teraflops. That is as a result of AMD’s RDNA 3 has a cut up clock area for effectivity functions. The entrance finish (render outputs and texturing items, maybe) runs at 2.5 GHz, whereas the shaders run at 2.3 GHz. We used the two.3 GHz worth because the teraflops come from the shaders. In fact, these are “Recreation Clocks,” which, not less than with RDNA 2, have been a conservative estimate of real-world clocks whereas operating precise video games. (That is the identical for Nvidia’s Ada Lovelace and Intel’s Arc Alchemist, which each are likely to run 150–250 MHz greater than the said enhance clock values in our testing.)

AMD additionally has a better enhance clock relative to the Recreation Clock, which is the place it will get the 61 teraflops determine — the enhance clock on the RX 7900 XT is 2.5 GHz. However, once more, we’ll want to check the {hardware} in quite a lot of video games to see the place the precise clocks land. With RDNA 2, we discovered the enhance clocks have been fairly constantly what we noticed in video games, perhaps even a bit low, so think about the 56.5 teraflops determine a really conservative estimate.

In fact, the larger deal is not how RX 7900 XT stacks up towards the RTX 4090 however somewhat the way it will compete with the RTX 4080. It has extra reminiscence and reminiscence bandwidth, plus 16% extra compute. So even when the efficiency per clock on the RDNA 3 shaders dropped a bit (extra on this in a second), AMD appears to be like prefer it needs to be very aggressive with Nvidia’s penultimate RTX 40-series half, particularly because it prices $200 much less.

With the high-level overview out of the way in which, let’s dig into some architectural particulars. Sadly, AMD is conserving some issues beneath wraps, so we’re not totally positive in regards to the reminiscence clocks proper now, and we have requested for extra data on different components of the structure. We’ll fill within the particulars as we get them, however some issues may stay unconfirmed till the RDNA 3 launch date on December 13.

AMD has mentioned quite a bit about vitality effectivity with the previous two generations of RDNA architectures, and RDNA 3 continues that focus. AMD claims as much as a 54% efficiency per watt enchancment in comparison with RDNA 2, which in flip was 54% higher PPW than RDNA. Up to now three generations, AMD’s effectivity has skyrocketed — and that is not simply advertising and marketing communicate.

In the event you have a look at the RX 6900 XT for instance, it is principally double the efficiency of the earlier era RX 5700 XT at 1440p extremely. In the meantime, it consumes 308W in our testing in comparison with 214W on the 5700 XT. In order that’s a 38% enchancment in effectivity, simply selecting the 2 quickest RDNA 2 and RDNA choices on the time of launch.

How does AMD proceed to enhance effectivity? In fact, a giant a part of the most recent soar comes because of the transfer from TSMC N7 to N5 (7nm to 5nm), however the architectural updates additionally assist.

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