Everything you need to know about AMD's "missing" 7800 XT and 7700 XT GPUs

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Everything you need to know about AMD's "missing" 7800 XT and 7700 XT GPUs

AMD introduced the Radeon RX 7900 XT and XTX GPUs last year. Then in May, the RX 7600 was introduced. But by the end of June, there is no word on AMD adding the 7800 XT and 7700 XT, and possibly other versions besides the XT, to the RDNA 3 series. So what exactly is going on?

The first thing to note is that the RX 7800 and 7700 cards are actually not that far behind; the RX 6700 XT was released in March 2021, so the general expectation was that the 7700 XT would be released this March. Worst case scenario, the 7700 XT will definitely be delayed a few months.

As for the 7800 XT, it's a bit more complicated: AMD rebranded it with the 7900 XT and 7900 XTX; when RDNA 2 launched in late 2020, the 6900 XT was the top card, with the 6800 XT directly below it, based on the same Navi 21 GPU.

In other words, the 7800 XT is already here and is just called the 7900 XT. But of course, there is still no plain RX 6800 successor that is not an XT. And then there is the aforementioned 6700 XT and 6700 non-XT.

Any way you look at it, there is a big hole in the middle of the RDNA 3 lineup. The latest rumors have appeared. One of the main points of contention is the so-called "leak" that the 7800 XT will actually be based on the same Navi 31 GPU as the existing 7900 XT and XTX.

It certainly makes sense, and indeed would not be a surprise, that the 7800 XT is based on the largest GPU available, whether it is the successor to the previous generation 6800 XT or a non-XT 6800, which is in line with AMD's previous approach.

Coincidentally, AMD has already reworked the Navi 31 that way with the Radeon Pro W7800. This is a professional GPU, not a gaming card. However, it uses a cut-down Navi 31 GPU with 70 CUs and 4,480 shaders. In case you forgot, the 7900 XT has 84 CUs and 5,376 shaders, and the 7900 XTX has 96 CUs and 6,144 shaders.

So AMD has something ready that can fill the 7800 XT role, what about the 7700 XT? That is also where things get a bit speculative. According to the best current information, the Navi 32 is a chiplet design like the Navi 31, but with a smaller graphics die and only four MCDs instead of six, the latter being a smaller chiplet that includes the cache and memory controller.

Exactly such a GPU was recently spotted in a display of silicon AMD laid out during an interview with CEO Lisa Su. 4 MCDs give the 7700 XT a memory bus width of 256 bits, but one of the 4 MCDs was inserted for packaging purposes It may be a dummy; placement of three MCDs would provide a 192-bit bus, making a 12 GB 7700 XT card possible.

In any case, the Navi 32 is generally thought to have 60 or 64 compute units, the upper limit for a 7700 XT card. However, some rumors suggest that the 7700 XT uses a cut-down of 54 CU Navi 32 GPUs

. Such a GPU would use all four MCDs, run on a 256-bit bus, and provide 16 GB of VRAM.

Incidentally, the Navi 32's maximum CU count of 60-64 also explains why it is unlikely to be used in the 7800 XT. The number of CUs is not sufficient for that class of GPUs. Even if they are faster than the older 6800 XT and its 72 RDNA 2-style CUs, it is unlikely.

Navi 31 is known for how these cards perform, and in fact, based on the W7800 Pro card, Igor's Lab recently ran calculations and found the 7800 XT to be slightly faster on average than the previous generation 6900 XT. Decent, but not spectacularly so. [On the other hand, the 7700 XT may be a bit more exciting: the 7800 XT is based on 70 RDNA 3 CUs, while the 6900 XT has 80 older RDNA 2 CUs. In other words, fewer CUs, but slightly higher performance. [The CU count for the 7700 XT is more uncertain. The old 6700 XT has 40 RDNA 2 CUs. So even 48 RDNA 3 CUs should be a reasonable step, and 54 CUs would be even better. Of course, it remains to be seen how many clocks the Navi 32 will have.

Of course, the same goes for the release dates of these new GPUs. Unfortunately, there is no firm date. Most existing rumors suggest a Q3, possibly September launch. Given the paucity of leaked information, it certainly does not appear that AMD's new GPUs are imminent.

The question that remains is why we haven't seen these new cards yet; one possibility is that AMD has a lot of previous generation 6700, 6800, and 6900 derivatives left that need shifting, and they don't like to add to that pile with new GPUs.

Another possibility is the Navi 32's technical issues. However, that still would not prevent a Navi 31-based 7800 XT from being released. Also, as we have reported many times, GPU sales are currently dismal. Therefore, the GPU oversupply theory seems a more plausible explanation.

And this is a summary of the best available information on AMD's next GPUs: TL;DR' The 7800 XT and 7700 XT will appear in September, with the possibility of non-XT variants.

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