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Test Results for AMD Zen 5

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Re: Test Results for AMD Zen 5

#21

Post by ryao »

ashvardanian wrote: post #5

> All vector units have full 512 bits capabilities except for memory writes. A 512-bit vector write instruction is executed as two 256-bit writes. That sounds like a weird design choice. Curious if this will affect memcpy-heavy workloads. Writes aside, Zen5 is taking much longer to roll out than I thought, and some of AMD's positioning is (almost expectedly) misleading, especially around AI. AMD's website claims Zen5…

AMD CPUs tend to have more memory bandwidth than Intel CPUs and inference is CPU bound, so their claim seems accurate to me.

Whether the core does a 512-bit write in 1 cycle or 2 because it is two 256-bit writes is immaterial. Memory bandwidth is bottlenecked by 64GB/sec per CCX. You need to use cores from multiple CCXs to get full bandwidth.

That said, the EYPC 9175F has 614.4GB/sec memory bandwidth and should be able to use all of it. I have one, although the machine is not yet assembled (Supermicro took 7 weeks to send me a motherboard, which delayed assembly), so I have no confirmed that it can use all of it yet.

Re: Test Results for AMD Zen 5

#23

Post by vhcr »

sushevff wrote: post #20
londons_explore wrote: post #15

> Integer vector instructions and floating point vector instructions now have the same latencies. There is very little reason to use integers for anything anymore. Loop counter? Why not make it a double - you never know when you might need an extra 0.5 loops at the end!

Totally. Can’t wait to access the 18463.637th record in my database plus or minus a record or thousand.

Doubles can represent integers exactly up to 2^52

Re: Test Results for AMD Zen 5

#24

Post by heraldgeezer »

varispeed wrote: post #18

Is it better than M4? If a laptop will need to be plugged in to deliver full performance, whilst blasting fans at full throttle, what is the point? (apart from server / workstation use, where you don't like MacOS or need different OS)

Windows laptops?

Desktops for gaming? AMD makes the best gaming CPUs with the X3D series.

Re: Test Results for AMD Zen 5

#25

Post by vient »

ashvardanian wrote: post #5

> All vector units have full 512 bits capabilities except for memory writes. A 512-bit vector write instruction is executed as two 256-bit writes. That sounds like a weird design choice. Curious if this will affect memcpy-heavy workloads. Writes aside, Zen5 is taking much longer to roll out than I thought, and some of AMD's positioning is (almost expectedly) misleading, especially around AI. AMD's website claims Zen5…

AMX is indeed a very strong feature for AI. I've compared Ryzen 9950X with w7-2495X using single-thread inference of some fp32/bf16 neural networks, and while Zen 5 is clearly better than Zen 4, Xeon is still a lot faster even considering that its frequency is almost 1GHz less.

Now, if we say "Zen5 is the leading consumer CPU for AI" then no objections can be made, consumer Intel models do not even support AVX-512.

Also, note that for inference they compare with Xeon 8592+ which is the top Emerald Rapids model. Not sure if comparison with Granite Rapids would have been more appropriate but they surely dodged the AMX bullet by testing FP32 precision instead of BF16.

Re: Test Results for AMD Zen 5

#26

Post by KetoManx64 »

heraldgeezer wrote: post #24
varispeed wrote: post #18

Is it better than M4? If a laptop will need to be plugged in to deliver full performance, whilst blasting fans at full throttle, what is the point? (apart from server / workstation use, where you don't like MacOS or need different OS)

Windows laptops? Desktops for gaming? AMD makes the best gaming CPUs with the X3D series.

What about actually doing something useful to bring prosuctive?

Re: Test Results for AMD Zen 5

#27

Post by mark-r »

vhcr wrote: post #23
sushevff wrote: post #20

Earlier quoted context omitted.

Totally. Can’t wait to access the 18463.637th record in my database plus or minus a record or thousand.

Doubles can represent integers exactly up to 2^52

Actually because of the implied upper bit in the format, it can go to 2^53.

Re: Test Results for AMD Zen 5

#28

Post by crest »

arrakark wrote: post #14
ashvardanian wrote: post #5

> All vector units have full 512 bits capabilities except for memory writes. A 512-bit vector write instruction is executed as two 256-bit writes. That sounds like a weird design choice. Curious if this will affect memcpy-heavy workloads. Writes aside, Zen5 is taking much longer to roll out than I thought, and some of AMD's positioning is (almost expectedly) misleading, especially around AI. AMD's website claims Zen5…

Cache-line bursts/beats tend to be standardized to 64B in lots of NoC architectures.

A 64B cache-line is the same size as an AVX-512 register.

Re: Test Results for AMD Zen 5

#29

Post by crest »

varispeed wrote: post #18

Is it better than M4? If a laptop will need to be plugged in to deliver full performance, whilst blasting fans at full throttle, what is the point? (apart from server / workstation use, where you don't like MacOS or need different OS)

Depends on your usecase. For a thin 14" laptop an M4 is probably the closer sweet spot, but for CPU heavy workloads Apple doesn't offer anything comparable to Threadripper or EPYC (lots of fast cores, enough memory and I/O bandwidth).
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