Radeon VII (2nd gen consumer Vega GPU)

[tServo]

Originally Posted by M344587487

Fingers crossed. If it has the full 1:2 ratio does that mean we can potentially saturate the memory at lower core clocks, or even do TF with the extra headroom with higher clocks? I wonder if it's possible to assign some CU's to gpuowl and others to mfakto, is SR-IOV needed for that or equivalent? I have doubts SR-IOV would make it to the consumer version.

From some guy on TWITTER !?!?!?!?!?!?

From Anandtech:

"on paper the new card only has a 9% compute throughput advantage. So it’s not on compute throughput where Radeon VII’s real winning charm lies"

[nomead]

Originally Posted by tServo

From some guy on TWITTER !?!?!?!?!?!?

"Some guy on Twitter" = Editor in Chief for Anandtech...

And the quote refers to FP32 performance. Later on in the same article though,
"The Vega 20 GPU does bring new compute features – particularly much higher FP64 compute throughput and new low-precision modes well-suited for neural network inferencing – but these features aren’t something consumers are likely to use."

[M344587487]

https://techgage.com/news/radeon-vii...4-performance/


https://www.hardocp.com/article/2019...tt_herkelman/2

[nomead]

Awww... That's it then, unfortunately my interest stopped right there.

[Mark Rose]

We'll have to see what it turns out to be. Ryan Smith specifically asked about it.

https://www.reddit.com/r/Amd/comment...apped/ee1jr5k/

[mackerel]

https://twitter.com/RyanSmithAT/stat...80805802733568

He's got the answer back, it's 1:8 rate.

[Mark Rose]

Originally Posted by mackerel

https://twitter.com/RyanSmithAT/stat...80805802733568

He's got the answer back, it's 1:8 rate.

Still a shame it's so crippled.

[preda]

Originally Posted by mackerel

https://twitter.com/RyanSmithAT/stat...80805802733568

He's got the answer back, it's 1:8 rate.

Interesting, that's double the DP rate of "classic Vega" (Vega64, Vega56). While a bit disappointing compared to 1:2 DP, may still be a good improvement in PRP especially matched with the higher-bandwidth RAM.

[M344587487]

Originally Posted by preda

Interesting, that's double the DP rate of "classic Vega" (Vega64, Vega56). While a bit disappointing compared to 1:2 DP, may still be a good improvement in PRP especially matched with the higher-bandwidth RAM.

Am I right in thinking that DP rate is the bottleneck for Vega 64 but that memory bandwidth comes a close second? Is it as simple as saying that for R7 to roughly match 2x Vega 64 throughput at the same clocks, it needed both double DP rate and double bandwidth (ignoring 4 CU difference)? Any potential bottlenecks other than those two? Other than higher is better I don't know how the specs translate into performance.

[preda]

Originally Posted by M344587487

Am I right in thinking that DP rate is the bottleneck for Vega 64 but that memory bandwidth comes a close second? Is it as simple as saying that for R7 to roughly match 2x Vega 64 throughput at the same clocks, it needed both double DP rate and double bandwidth (ignoring 4 CU difference)? Any potential bottlenecks other than those two? Other than higher is better I don't know how the specs translate into performance.

2x would be amazing. In practice I would be very happy if I see a 50% speedup.

About memory, it is my impression that the latency did not improve much, but the bandwidth doubled. But to take advantage of this, better occupancy would be required (double the number of memory operations in flight), and this is not easily achievable because of other limiting resources: LDS memory and nb. of registers (VGPRs) that remain unchanged I guess.

About compute, the parts that aren't DP (e.g. pointer arithmetic, other integer e.g. carry, logic) remain unchanged, and this will reduce the observed speedup.

IMO another limiting factor for GCN performance is still the compiler, after so many years: the compiler does a rather poor job at generating highly efficient code (not an easy task I agree).

OTOH the better cooling will help, and allow the card to be higher clocked without thermal throttling (which is a problem on Vega64 blower cooler)

Originally Posted by preda

2x would be amazing. In practice I would be very happy if I see a 50% speedup.

About memory, it is my impression that the latency did not improve much, but the bandwidth doubled. But to take advantage of this, better occupancy would be required (double the number of memory operations in flight), and this is not easily achievable because of other limiting resources: LDS memory and nb. of registers (VGPRs) that remain unchanged I guess.

About compute, the parts that aren't DP (e.g. pointer arithmetic, other integer e.g. carry, logic) remain unchanged, and this will reduce the observed speedup.

IMO another limiting factor for GCN performance is still the compiler, after so many years: the compiler does a rather poor job at generating highly efficient code (not an easy task I agree).

OTOH the better cooling will help, and allow the card to be higher clocked without thermal throttling (which is a problem on Vega64 blower cooler)

I am procrastinating the buy a new more powerful gpu, do you have any plans to optimize gpuowl for large numbers ?