Originally posted by atomsymbol
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CPUs From 2004 Against AMD's New 64-Core Threadripper 3990X + Tests Against FX-9590
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Originally posted by Zucca View PostOuch.
My FX-8350 now seems quite a slow CPU... :|
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Originally posted by atomsymbol
Some notes:- The multiplication almost never overflows in this case because the loop terminates due to (i*i <= test), where "test" is an int and "i" increases by 1 per loop iteration
- The C/C++ type int is 32-bit even on 64-bit systems
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Originally posted by atomsymbol
Some notes:- The multiplication almost never overflows in this case because the loop terminates due to (i*i <= test), where "test" is an int and "i" increases by 1 per loop iteration
- The C/C++ type int is 32-bit even on 64-bit systems
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Originally posted by Raka555 View Post
I repeated it several times.
Even my 4600u intel laptop is faster than the 3700x with this.
You can check for yourself:
Compile with "gcc -O3 prime.c -o prime_gcc"
However, it's safe to say that integer division isn't a strong suit for AMD's current architecture. I think most non-trivial number crunching applications are a lot smarter about how they do that kind of thing and would be using AVX(2/512) instead.
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Originally posted by Zan Lynx View Post
Automatic integer promotion rules happen, I think. I'm almost sure I've seen the multiply happen in 64-bits and then compare against a 64 bit register value even if it's an int. Because otherwise the compiler would have to output lame assembly to truncate the result, and there's a reason int overflow is undefined. Especially on uarch like PowerPC. I'll have to compile this one and look at the machine code I guess.
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Originally posted by tg-- View Post
Funny, you mention benchmarks designed for that purpose and in the next breath mention a benchmark designed for that purpose to make the opposite point.
The prime calculator likely uses a special code path for Intel's AVX which the 3770 supports, and will fall back to a generic, slow, codepath for AMD (where the Ryzens now would support the same AVX that 3770 did).
The threadripper will outperform the old 3770 in any metric at any time, even intel-optimized AVX. It just can't outperform it if it can't use its accelerated paths, which is a decision of the software developer.
https://www.phoronix.com/forums/foru...29#post1158629Last edited by Raka555; 09 February 2020, 04:51 AM.
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Originally posted by Raka555 View Postvs Raspberry PI ?
It is actually not that impressive that it is only 4x faster with compiling the kernel and only 2x faster encoding an mp3 than the AMD FX-9590 with its 64/128 against 8/8...
For me lots of cores only looks good in benchmarks designed for that purpose.
In the "real world" you still get bad diminishing returns ...
Yesterday I ran a program that calculates prime numbers and I was not impressed that my 2012 model i7-3770 (3.4GHz/3.9GHZ) did it in 4s versus my "shinny new" ryzen7-3700x (3.6Ghz/4.4GHz) which only managed 8s....
Running bloatware is where the ryzens shine with all their cache, but pure calculations intel seems to still be far ahead...
It is obvious that you are quite ignorant of how cpus work, and you think calculating pi is somehow a good indicator of cpu performance. If you think that way, then please by all means, donate your Ryzen7-3700x somewhere and upgrade your cpu performance to the i7-3770. Moron.
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