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Old 2018-12-23, 02:06   #353
NookieN
 
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Quote:
Originally Posted by chalsall View Post
OK, that suggests your games and your video encoders are not terribly optimized. But an important thing to take into consideration is Prime95 /can/ slow down the responsiveness of your other apps.

Every "use case" is different. Do "what makes sense" for you.
Yeah that's a good point, the encoding likely is slower when Prime is running. I agree that it really depends on your use cases, and that was my point. I would not encourage someone to just turn off HT unless they know that it is in fact detrimental to their intended workload.
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Old 2018-12-23, 02:29   #354
chalsall
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I would not encourage someone to just turn off HT unless they know that it is in fact detrimental to their intended workload.
Sigh... That is the exact opposite of what I intended to communicate.
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Old 2018-12-23, 03:12   #355
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Originally Posted by Prime95 View Post
Run version 29.5 -- it makes use of the AVX-512 instructions (about 15% faster). You'll have to dig through the 29.5 thread to find the link to the Windows executable.

Your goal is to get to 50% CPU usage -- hyperthreading will slow down prime95. You can leave hyperthreading on in the BIOS.
OK from all the answers it sounds like Prime95 is probably doing just fine at configuring itself on the defaults, and 65% CPU is not low at all.

Sounds like a good idea to shift to 29.5 if it goes 15% faster.

ms/iter for workers 1 through 6 is averaging
8.3
8.2
5.8
23
23
23

My RAM is rated at 3000MHz, who knows what it's clocked at though.
ETAs appear to be the output of a high quality random number generator.
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Old 2018-12-23, 03:20   #356
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Originally Posted by theonetruepath View Post
My RAM is rated at 3000MHz, who knows what it's clocked at though.
Tools like CPU-Z can tell you. Note that some tools, CPU-Z included, report the clockspeed, not the "double-data-rate" (hence the term DDR) transfers-per-second, so if your RAM was running at its rated speed it would report as 1500MHz in CPU-Z.
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Old 2018-12-23, 04:04   #357
theonetruepath
 
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Quote:
Originally Posted by James Heinrich View Post
Tools like CPU-Z can tell you. Note that some tools, CPU-Z included, report the clockspeed, not the "double-data-rate" (hence the term DDR) transfers-per-second, so if your RAM was running at its rated speed it would report as 1500MHz in CPU-Z.
Looks like my RAM is underclocked, CPU-Z says 1067 instead of 1500. Might have to dig into the BIOS settings.

I tried Prime95-29.5 build 5 and the subsequent "special build for someone", both crash immediately, I'll wait for the final version there.
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Old 2018-12-23, 05:02   #358
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Originally Posted by theonetruepath View Post
Looks like my RAM is underclocked, CPU-Z says 1067 instead of 1500. Might have to dig into the BIOS settings.
RAM now running at 1500MHz.
Prime95 29.4 now reports
Workers 1 through 6: cores/ms per iter
3/6.24
3/6.6
4/5.1
1/19.35
1/19.4
1/19.4

For some reason I'm trying to use 13 cores, which is why task manager says I'm at 65%
So should I reduce this to 10 for better throughput?
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Old 2018-12-23, 05:04   #359
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Quote:
Originally Posted by theonetruepath View Post
Looks like my RAM is underclocked, CPU-Z says 1067 instead of 1500. Might have to dig into the BIOS settings.
Assuming your CPU is the i9-7900X, note that the max (officially) supported RAM speed is DDR4-2666. Having higher speed-rated RAM isn't a bad thing though, as you may be able to run it at lower timings and that could have as much (or more) benefit as the higher clock speed. On a supported motherboard, the best available RAM settings are likely listed under an "XMP" profile -- again consult CPU-Z under the "SPD" tab to see available timing specs for your specific RAM.

Last fiddled with by James Heinrich on 2018-12-23 at 05:06
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Old 2018-12-23, 05:16   #360
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Quote:
Originally Posted by James Heinrich View Post
Assuming your CPU is the i9-7900X, note that the max (officially) supported RAM speed is DDR4-2666. Having higher speed-rated RAM isn't a bad thing though, as you may be able to run it at lower timings and that could have as much (or more) benefit as the higher clock speed. On a supported motherboard, the best available RAM settings are likely listed under an "XMP" profile -- again consult CPU-Z under the "SPD" tab to see available timing specs for your specific RAM.
Yup I turned on the XMP profile. Seems stable so far. Mobo is a Gigabyte Aorus Gaming 9 v1.
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Old 2018-12-23, 06:19   #361
Prime95
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Originally Posted by theonetruepath View Post
For some reason I'm trying to use 13 cores, which is why task manager says I'm at 65%
So should I reduce this to 10 for better throughput?
Absolutely.
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Old 2018-12-23, 06:41   #362
theonetruepath
 
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Originally Posted by Prime95 View Post
Absolutely.
OK I reduced to three workers. Timings for three workers are now (cores/ms per iter)
3/4.8
3/4.8
4/3.5

So the overall average time per iteration drops from around 12.2 (13 cores) to around 4.4 (10 cores)

I'm assuming I can just average these since they are all "10000 iteration" times.

You aren't kidding when you say it slows down if using extra cores...

Any idea why version 29.5 crashes on my system - is there some diagnostic info I can scrape together for you?
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Old 2018-12-23, 07:21   #363
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Quote:
Originally Posted by theonetruepath View Post

I'm assuming I can just average these since they are all "10000 iteration" times.
Heh of course you can't. So I took an arbitrary time period and worked out how many iterations each worker contributed in that time, then worked out net msecs per iter for the system
13 cores is 1.62 ms/iter
10 cores is 1.42 ms/iter

Maybe the program could work this out from time to time...
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