Discussion RDNA 5 / UDNA (CDNA Next) speculation

[511]

when is it going to launch cause i know for sure it will be on N3E/P.

 

[marees]

when is it going to launch cause i know for sure it will be on N3E/P.

Along with xbox next year

Xbox nov
RDNA 5 probably dec-31st

 

[511]

Along with xbox next year

Xbox nov
RDNA 5 probably dec-31st

Xbox I don't have high hopes for next year lol ngl.

 

[GodisanAtheist]

True, but almost certainly not abandoning IF caching schemes. GDDR7 alone cannot replace the bandwidth amplification of a large cache.

- New GDDR probably means they can shrink IC and claw back some die space though.

IC is a good crutch while AMD uses GDDR6, while NV went with more exotic RAM.

GDDR7 won't eliminate the need for IC, but will likely minimize it.

 

[basix]

"Magnus" could use 384bit + 48 MByte IF$ instead of 96 MByte. In the end a tradeoff between effective bandwidth and amount of VRAM.

 

[maddie]

- New GDDR probably means they can shrink IC and claw back some die space though.

IC is a good crutch while AMD uses GDDR6, while NV went with more exotic RAM.

GDDR7 won't eliminate the need for IC, but will likely minimize it.

IC was used effectively even when NVIDIA was also on GDDR6.

"Magnus" could use 384bit + 48 MByte IF$ instead of 96 MByte. In the end a tradeoff between effective bandwidth and amount of VRAM.

I don't think cache can reduce the need for "amount of VRAM".

It amplifies bandwidth, so allows a smaller bus width. We should remember, the space needed for memory controllers is reduced, so this needs to be factored in the total cache+memory controllers area. The penalty might be a lot smaller than we think as logic shrinks faster than analog. Reduced power is another benefit.

 

[itsmydamnation]

Also rtrt drives latency , reducing cache will hurt rtrt regardless of overall bandwidth.

 

[reaperrr3]

IC is also more power efficient than VRAM access, this was one big factor of RDNA2's massive perf/W improvement.

48MB might be enough for 80 CUs running at more modest clocks in a console (remember previous console SoCs had no GPU IC at all), but for a 96 CU desktop GPU with 20+% higher CU IPC and clocked to 3+ GHz, 96MB might be necessary to hit their perf targets at 4K and RT/PT in general, despite GDDR7.

FWIW, Nvidia didn't back down on their L2 sizes with Blackwell despite GDDR7 either, and NV is no less margin-oriented than AMD.