AMD Simulated RX 7800 XT Performs Similarly to RX 6800 XT

AND Radeon RX 7000 and RX 6000
(Image credit: AMD)

Igor's Lab has taken on the task of simulating an RX 7800 XT to see what performance might look like. This was done using AMD's new Radeon Pro W7800 graphics card, with half the memory otherwise occupied. Igor's simulation results and theoretical calculations put this theoretical 7800 XT roughly between an RX 6800 XT and RX 6900 XT, or between Nvidia's competing RTX 4070 and 4070 Ti.

The Radeon Pro W7800 is part of AMD's W7000 series workstation GPUs, featuring its latest RDNA 3 GPU architecture. The GPU sports 70 compute units using AMD's Navi 31 die, with 32GB of memory and a total board power rating of 260W. Due to this, the W7800 is arguably the best current candidate for simulating a theoretical RX 7800 XT. That's because it has a 256-bit memory interface, the same as the rumored RX 7800 XT; disabling half of the VRAM should be a reasonably close stand-in for the future GPU.

Igor provided two different test scenarios. The first involved physically simulating a 7800 XT by artificially disabling half of the memory, leaving the GPU with 16GB of GDDR6 VRAM. The second used theoretical calculations taken from the power efficiency results of the RX 7900 XT. The latter was done to attempt to provide a "more accurate" picture of how an actual RX 7800 XT may perform, since the W7800 is tuned for efficiency rather than performance.

It hopefully goes without saying, but both scenarios are at best an estimate of performance. There are multiple issues, including final clock speeds, core counts, whether the "disabled" VRAM truly mimics a 16GB card, drivers, and more. Igor tested at 1080p, 1440p, and 4K. The "simulated" and "calculated" W7800 results were relatively close, with the simulated results looking similar to an RX 6800 XT while the calculated results look more like an RX 6900 XT. Our GPU benchmarks hierarchy incidentally puts the 6900 XT about 7% ahead of the 6800 XT. Here's the overall 1440p chart:

Igor's Theoretical RX 7800 XT Benchmark, 1440p

(Image credit: Igor's Lab)
Aaron Klotz
Contributing Writer

Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.

  • lmcnabney
    If a 7800XT performs the same as a 6800XT I would call that an epic failure.
    Reply
  • Alvar "Miles" Udell
    Even if it only matches the performance of the existing RX 6800 XT, if it has a similar price and uses less power while providing a few new extras (like AV1 encoding support), it could still be a decent card.

    No, that would be a very good reason not to buy it, and for TH and all other reputable review sites to not recommend it for purchase.
    Reply
  • -Fran-
    There's 2 bars in that graph, so the theoretical performance should land in between the two: simulated and "calculated", where the latter should be closer to what we all should expect.

    But as with everything, it'll come down to price. I think by now AMD knows this can't be over $500, unless they want it to sit on shelves forever.

    Regards.
    Reply
  • while rumors indicate the RX 7800 XT will use a Navi 22 GCD with 60 (possibly 64) CUs.

    No, it is NAVI 32. Correct the typo.

    Also I agree with other points you made in the article, but the simulated specs assume that the card would feature 70 Compute Units, memory clocked at 20 Gbps and game clock likely above 2 GHz, but this is not set on stone. This will cause a huge discrepancy.

    It is unlikely the 7800XT will sport 70 CUs.

    While he achieved this feat via the memtestcl program, for the VRAM, since RDNA 3 no longer allows to emulate the cards directly, the simulation is far from perfect. This is just an educated guess at the most.

    This is evident from the results, since the simulated GPU shows a very small performance advantage, - 4% (1080p), 8% (1440p) and 12.5% (2160p), over the previous gen RX 6800 XT SKU. This won't be the case in real world gaming since the NAVI 32 silicon and the specs are NOT even finalized yet.

    It is unlikely AMD would release a card that is only 4/8/12% faster than the previous gen offering.
    Reply
  • Also, using and simulating a NAVI 31 die for a NAVI 32 dies makes little sense. Just because the pro card features a 256-bit memory interface doesn't mean the final silicon of Navi 32 will also sport the same bus width. It might be possible, but at this point this is just an educated guess.
    Reply
  • MergleBergle
    Pretty sure "grain of salt" applies to the suggestions of this simulation. Esp since the simulation is with a pro card, not a gaming card.
    Reply
  • Elusive Ruse
    Why would AMD release a 7800XT that is equal to 6800XT? That sounds so implausible.
    Reply
  • atomicWAR
    AMD keeps pulling Nvidia moves this gen. Its more than a little disheartening.

    Metal Messiah. said:
    No, it is NAVI 32. Correct the typo.

    Also I agree with other points you made in the article, but the simulated specs assume that the card would feature 70 Compute Units, memory clocked at 20 Gbps and game clock likely above 2 GHz, but this is not set on stone. This will cause a huge discrepancy.

    It is unlikely the 7800XT will sport 70 CUs.

    While he achieved this feat via the memtestcl program, for the VRAM, since RDNA 3 no longer allows to emulate the cards directly, the simulation is far from perfect. This is just an educated guess at the most.

    This is evident from the results, since the simulated GPU shows a very small performance advantage, - 4% (1080p), 8% (1440p) and 12.5% (2160p), over the previous gen RX 6800 XT SKU. This won't be the case in real world gaming since the NAVI 32 silicon and the specs are NOT even finalized yet.

    It is unlikely AMD would release a card that is only 4/8/12% faster than the previous gen offering.
    So true but it is better than nothing.
    Reply
  • atomicWAR
    Elusive Ruse said:
    Why would AMD release a 7800XT that is equal to 6800XT? That sounds so implausible.
    Why would Nvidia release a RTX 4060 Ti that is barely better than last gen and worse in some cases (1440P res usually). Yet it happened.
    Reply
  • Ar558
    Looks like this really confirms the end of Moore's law and 5% increases gen to gen for 10% price increases are now the new norm.
    Reply