AMD’s upcoming Radeon RX 7800XT graphics card will allegedly leverage a cutdown Navi 31 die instead of the previously rumored Navi 32. According to Moore’s Law is Dead, Navi 32 is still not ready for the retail market, and we’ll be seeing a partially disabled Navi 31 at the heart of the RX 7800XT. This doesn’t sound far-fetched, as AMD already has a workstation part, the W7800, based on the same configuration on the market.
| RX 7900 XTX | RX 7900 XT | RX 7800XT | RX 6800 XT | |
| Compute units | 96 | 84 | 70 | 72 |
| Shaders | 6,144 | 5,376 | 4,480 | 4,608 |
| Ray Accelerators | 96 | 84 | 70 | 72 |
| Memory | 24GB GDDR6 | 20GB GDDR6 | 16GB GDDR6 | 16GB GDDR6 |
| Memory Speed | 20Gbps | 20Gbps | 20Gbps | 16Gbps |
| Memory Bus Size | 384-bit | 320-bit | 256-bit | 256-bit |
| Game Clock Speed | 2.3GHz | 2GHz | ? | 2GHz |
| L3 Cache | 96MB | 80MB | 64MB | 128MB |
| TBP | 355W | 315W | ? | 300W |
| MSRP | $999 | $899 | ? | $649 |
A while back, Igor (Igor’s Lab) thoroughly tested the Radeon PRO W7800 as a simulated RX 7800 XT and got some interesting results. The Radeon PRO W7800 is a workstation card based on Navi 31. It is a partially disabled RX 7900 XT with 70 CUs (down from 96 CUs on the RX 7900 XTX). Furthermore, it comes with only two MCDs, reducing the bus width to 256-bit and the Infinity cache to 64MB.
Being a creator card, it comes with a relatively lower core clock of just 1.85GHz (which can be increased to 2.5GHz). Igor found that the Radeon RX 7800XT (based on the PRO W7800 results) will likely be 10-15% faster than the RX 6800 XT, 10-20%, if you want to be more cautious. Interestingly, the 7800XT offered the highest gains, compared to the RX 6800 XT at 4K, registering an average gain of 12.5%.
The Radeon RX 6800 XT averaged 59 FPS at 4K, while the RX 7800 XT averaged 66.4 FPS. At 1440p, the RX 7800XT registered 119 FPS, while the RX 6800 XT produced 108 FPS, a lead of just 8%.
Tom from MLID claims that the Radeon RX 7800XT will leverage the Navi 31 GPU leaving Navi 32 for the RX 7800 (non-XT). Going with the former will certainly help with yields while eliminating the work associated with validating and testing a brand-new GPU. If this is true, the Radeon RX 7800M XT (leaked earlier this month) may also be a Navi 31 derivative. Leveraging a lower-tier die on mobile is the norm, but going by the performance, it’s likely the same SKU.
