I've been thinking of when will the RDNA4 cards come out.
As MILD mentioned RDNA 4 will come out around Q3 2024. I don't think there will be RDNA 3.5 refresh cards or RDNA 3 refresh cards out next year.
I think RDNA4 will be very similar to RDNA3 apart from very small arch improvements and update to Raytracing core.
There were rumors in 2022 that AMD had issues with TSMC 3nm node and that they will be using 4nm. Current rumors don't say anything about which node will RDNA4 use but, seeing that TSMC N3E 3nm node is just being put in production and others will be using it, makes sense that AMD has to use the 4nm node in 2024. This could make AMD release the RDNA 4 before Nvidia does its new series. So, I'm thinking RDNA4 could come out end of May and be available in June 2024.
Further, I was looking at how big the RDNA 4 flagship chip will be in mm2 and what its performance could be. Taking the N31 which is based on 5nm and 6nm nodes and combined size of 530mm2. An RDNA4 best would be around 370mm to 450mm2 chip with 90-96 CUs like Rx7900 series, but with 256Bit bus, faster memory since it will use Gddr7 and rated TDP of below 280W. I came to this conclusion that 4nm TSMC node is a very small improvement in transistor density, of just 6% for the N4, (N4x or Nvidia specific 4N might be a bit more).
Looking at the 4nm node and doing the math is no wonder that AMD can't produce a high-end GPU next year because by my math comes out that a 20-30% more performat GPU then a RX7900xtx would have to be bigger then 680mm2 and have a TDP of 410W, that's what the 4nm node does.
But here are the all the good things, the GPU, let's say it's called Rx 8800 XT is out in middle of next year has 16gb of Vram for 600$, identical performance in raster compared to Rx 7900 XTX and somewhat better performance in raytracing.
There are two AMD patents on raytracing that I’ve read few months back. The first one, released 1 year prior to first RDNA 2 GPU, talks about raytracing core. But the second one, it was released in June this year. So, the latest AMD patent describes GPU withing its raytracing core, addition of a hardware specific traversal engine and specific BVH memory cache. Not to go into details, from what I understand of the two patents first patent describes raytracing core in RDNA 2&3 and the second patent describes similar but a much improved way of doing raytracing. I’m hopeful we will see this is RDNA4(the patent did arrive this june and next june we’ll have RDNA 4 card so it matches the schedule prior to RDNA2) (https://www.freepatentsonline.com/20230206543.pdf)
One of the fun benefits of the Navi31 die, AMD just needs to adapt the Navi31 main die to the newer fabrication node plus minor updates and polish. The I/O dies hold the memory controllers, so adapting to GDDR7 is just redesigning the I/O dies. If the RDNA4 I/O dies support GDDR7 and are compatible with Navi31, making the Navi31 refresh support GDDR7 won't require too much effort.
That would be a good solution if the card was massively ahead of the XTX. 4090 levels at least. And it would still be behind in RT likely.
Yes, but would this be usefull?
It depends on where bottlenecks lie. Commonly, VRAM bandwidth is such a major bottleneck that graphics engines are designed and tuned to take advantage of the excess GPU power over the VRAM bandwidth limits. For an object in VRAM to be rendered, it must occupy VRAM bandwidth per frame. All the extra VRAM capacity that many tout just allows bigger levels to be stored in VRAM without the need for memory management. If you want higher detail objects in VRAM and rendering them as well, you need bandwidth to accompany the capacity.
Given ray tracing typically increases VRAM memory usage by a substantial amount, it is a wonder, and worthy experiment to see how much VRAM bandwidth is the bottleneck for such performance.