There is an update for AMD’s general purpose ROCm GPU software reportedly revealed specs for Navi 32 and Navi 33, (opens in new tab) the following graphics chips likely to be released in the RDNA 3 series, also known as Radeon RX-7000 series. Exactly where the new chips fit AMD’s new Radeon RX 7000 series (opens in new tab) is the really big question.
Are these chips the basis of the upcoming Radeon RX 7800 and 7700 GPUs? Hold that thought as we reflect on the new information that has emerged. Buried deep in a ROCm file named “performance.hpp” are references to both Navi 32 and Navi. But the really critical numbers in the file are 60 and 32, and we’re talking about CUs or Compute Units. To understand those numbers, the Navi 31 chip in the AMD Radeon RX 7900 XT and XTX graphics cards runs 96 CUs.
Assume the same CU subtree for all three GPUs where each CU contains 64 stream processors and you end up with 6,144 stream processors on Navi 31, 3,840 on Navi 32, and 2,048 on Navi 33. For more context, the outgoing Navi 21 GPU in the Radeon RX 6900XT (opens in new tab) has 80 CUs and 5,120 processors, while Navi 22 as found in the 6700 XT rocked 40 CUs and 2,560 processors.
To complicate things a bit, the stream processors in the new RDNA 3 chips are double-pumped and capable of handling twice as many FP32 operations as an RDNA 2 stream processor, but not double the whole math. It’s annoyingly complicated stuff, which means Navi 31 sometimes acts like it has 12,288 processors, but not always.
The same goes for Navi 32 and Navi 33. Navi 32 would therefore either have 3,840 processors, which doesn’t look that impressive if the previous generation RDNA 2 architecture expanded to 5,120, or you could call it 7,680 processors. , which sounds pretty sweet.
(opens in new tab)
So, where in AMD’s new RX 7000 series are Navi 32 and Navi 33 likely to fall? For the previous RDNA 2 generation, AMD actually has the Radeon RX 6800 and 6800 XT (opens in new tab) on the big Navi 21. Unfortunately, just as Nvidia relegated the GeForce RTX 4080 to the smaller AD104 chip instead of relying on the larger AD102 beast, it seems likely AMD will do the same this time around.
In other words, the Radeon RX 7800 and 7800 XT will likely be based on Navi 32 this time around. Therefore, at best, the 7800 XT will offer 62.5 percent of the physical hardware of the 7900 XTX. By comparison, the old 6800 XT is 90 percent of a 6900 XT. Like Nvidia, the gap between the top tier card and the next rung down seems to be widening for this generation of AMD boards.
(opens in new tab)
As for Navi 33, that chip would then form the basis of the Radeon RX 7700 and 7700 XT. Notably, Navi 33 is expected to have 128-bit memory, a step down from the Radeon RX 6700 XT’s 192-bit bus. (opens in new tab) Additionally, the smaller of the two ways of measuring the number of stream processors would drop the 7700 XT down to just 2,048 processors from the 6700 XT’s 2,560.
Your next device
If all that doesn’t sound promising, clock speed is the joker that could change everything. According to AMD, RDNA 3 is designed for clock speeds of 3 GHz and above. For reasons not yet clear, AMD has failed to get close to that figure with Navi 31, the first RDNA 3 GPU off the blocks.
However, clock speeds of up to 3.3 GHz or more for various RDNA 3 GPUs have been rumored for some time now. The 6700 XT’s maximum boost clock, for reference, is just under 2.6 GHz. All this means that the upcoming 7800 XT and 7700 XT graphics cards can still deliver a very healthy performance boost over AMD’s existing mid and upper mid-tier GPUs, provided it delivers those 3GHz-plus frequencies on the smaller chips .