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markovchain

macrumors member
Original poster
Mar 30, 2015
72
18
Hello,

I've googled the turbo steps of Intel Xeon W processors used by iMac Pro but to no avail.

AFAIK the so-called turbo frequency only apply to single core. That means when the rest often scale down to lower CPU frequency. With skylake AVX512, it is even lower.
See below Xeon Silver 4114, the AVX512 frequency is down from 2.2GHz to 1.1GHz

Normal 2,200 MHz
3,000 MHz 3,000 MHz 2,800 MHz 2,800 MHz 2,700 MHz 2,700 MHz 2,700 MHz 2,700 MHz 2,500 MHz 2,500 MHz
AVX2 1,800 MHz
2,900 MHz 2,900 MHz 2,700 MHz 2,700 MHz 2,300 MHz 2,300 MHz 2,300 MHz 2,300 MHz 2,200 MHz 2,200 MHz
AVX512 1,100 MHz
1,800 MHz 1,800 MHz 1,600 MHz 1,600 MHz 1,500 MHz 1,500 MHz 1,500 MHz 1,500 MHz 1,400 MHz 1,400 MHz

It seems Intel never release the turbo steps frequency for Xeon W processors. Isn't it a bit risky to pay for iMac Pro?

EDIT: I am planning to run some AVX2 AVX512 on iMac Pro so worry the performance hit due to downscaled frequency!!!
 
Why risky? They operate Just like the non W chips, albeit at slightly lower frequencies. For what it's worth the 8-core iMac Pro settles at 3.9 GHz when all cores are used.
 
My $0.02 i thought the Xeon class chips are designed for server class of usage I.e. if you are a pro who is going to be loading up CPUs a lot for compute capability for your business processing then they are the ones to go for versus pimped up consumer grade chips (like mine iMac i7 which I only occasionally ramp up load).

Not sure what the risk is? A lot of people seem to get far too focused on the very marginal frequency differences versus overall system-wide throughput performance anyway.
 
Have you run some AVX codes and see ALL codes running at 3.9 GHZ?

Or does the Xeon W suffer from the same performance hit like Xeon scalable processors like this https://blog.cloudflare.com/on-the-dangers-of-intels-frequency-scaling/
Ah, I misunderstood. I have no real understanding of AVX, but I would expect Xeon W to perform similarly to non-W. Your answer will probably only come from giving it a try. You can always return if it doesn't meet your expectation.
 
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