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Old 9th November 2018, 18:34   #81  |  Link
nevcairiel
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AVX with 128-bit registers has small minor benefits, usually because there happen to be some instrustrictons that may do the job better, and because AVX allows more efficient use of some other instructions (ie. distinct destination registers for some instructions, instead of an implied one). The differences to SSE1/2/3/4.1 versions of the same code (which also are 128-bit) is relatively small, maybe 5-10% (for a single given function), while doubling the register size to 256 can in an ideal case of course be up to twice as fast.
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Old 10th November 2018, 09:00   #82  |  Link
Wolfberry
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Quote:
128-bit AVX is special. There is no reason to use it on Intel processors since SSE2 is just as fast.
However, on AMD processors we can both use FMA4, and 128-bit SIMD is better than 256-bit since core pairs in a compute unit can execute two 128-bit instructions independently.
This is from a comment in fftw3 configure.ac about --enable-avx-128-fma, which in turn enables the use of FMA4 instruction. (-mfma4)
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Old 10th November 2018, 09:35   #83  |  Link
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Intel's strong PR and marketing teams are trying really hard with tons of money behind them to persuade people that more cores are useless or at least not necessary.

It's the same old story for the dark ages of 2011 - 2017 era, when the same teams were telling us that the Core i3 2C/4T - Core i5 4C/4T - Core i7 4C/8T scheme is the best that we could ever had.

No more than 4 cores for mainstream desktop, ordered Intel.

If you wanted more, you should pay 2000$ to buy 10 cores of Broadwell-E 6950X in 2017.

On March 2017 a world revolution took place.

The revolution of Zen architecture and the first implementation of RyZen processor for mainstream desktop, using 8C/16T in a very affordable price of 350$ - 500$ (initially)

Nowadays, you can buy 32C/64T for 1800$ from AMD, when Intel still sells 18C/36T for 2000$ - even this means 80% more cores for the same price just a year later for Intel.

Cascade-AP, a one-off processor from Intel, mimicks the Zen first generation architecture for servers (EPYC) and rises the sum of cores to 48 from 28 of Skylake-EP using GLUE (as Intel called Infinity Fabric of Zen architecture) to add two Skylake 24C processors to one Cascade 48C.

Intel is trying hard to be as less humiliated as possible compared to the absolute monster of EPYC 2, a multi-die (8+1) CPU of 64C/128T adding PCIe v4.0 and Infinity Fabric 2 to the equation.

Intel guys, please relax...

If you can't avoid something, just enjoy it.

It's coming!
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Old 11th November 2018, 14:30   #84  |  Link
Racer
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Quote:
Originally Posted by Atak_Snajpera View Post
Looks like there are some serious issues with scheduler in windows. 5 instances of x265 running and 2990WX just chokes


Source -> https://www.xfastest.com/thread-221870-1-1.html
Is there actually an updated benchmark with adjusted numa pools or did anybody check if this gives an performance improvement for the 2990WX?

Code:
Instance 1 = --numa-pools "+,-,-,-" 
Instance 2 = --numa-pools "-,+,-,-"
Instance 3 = --numa-pools "-,-,+,-"
Instance 4 = --numa-pools "-,-,-,+"
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Old 11th November 2018, 18:37   #85  |  Link
Atak_Snajpera
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Do you have access to 2990wx?
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