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Old 2021-05-17, 13:28   #1
JuanTutors
 
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Default PC running about 60% faster than ever?

My desktop, a Samsung with an Intel Core i5-7400T CPU at 2.40GHz is currently running about 60% faster than it ever has. Not to look a gift horse in the mouth, but this doesn't even seem reasonable, to be frank. The fastest that it has ever shown me to process a 100M digit PRP is about 60 ms/iteration. Right now it's supposedly doing 37 ms/iteration. Does this make sense? Is it that my computer was running way slower in the past and just now has figured out some bottleneck issue?
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Old 2021-05-17, 15:09   #2
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Have you changed Prime95 version recently? It could be that you were on a non-SIMD build and are now using AVX2.
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Old 2021-05-17, 16:33   #3
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Quote:
Originally Posted by JuanTutors View Post
My desktop, a Samsung with an Intel Core i5-7400T CPU at 2.40GHz is currently running about 60% faster than it ever has. Not to look a gift horse in the mouth, but this doesn't even seem reasonable, to be frank. The fastest that it has ever shown me to process a 100M digit PRP is about 60 ms/iteration. Right now it's supposedly doing 37 ms/iteration. Does this make sense? Is it that my computer was running way slower in the past and just now has figured out some bottleneck issue?
Is this using all 4 cores or 1 core per worker? How many workers? If you're running 1 worker with all 4 cores, neither time is particularly fast.

What is the clock speed the CPU is running at?

What is your memory config (# sticks, speed, capacity)?

Finally, what changed recently that could cause the speed improvement?
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Old 2021-05-17, 16:59   #4
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Is this using all 4 cores or 1 core per worker? How many workers? If you're running 1 worker with all 4 cores, neither time is particularly fast.

What is the clock speed the CPU is running at?

What is your memory config (# sticks, speed, capacity)?

Finally, what changed recently that could cause the speed improvement?
It's running at 2.4 GHz, one thread doing one exponent only, not overclocked or anything. It has 12GB ram, and I don't know the exact configuration of that ram. And about the change, actually I haven't made any changes, and the computer has actually been giving me MORE trouble than usual. (10 minute restart time, glitchy screen effects hinting at a video card issue, etc)
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Old 2021-05-17, 17:00   #5
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Quote:
Originally Posted by M344587487 View Post
Have you changed Prime95 version recently? It could be that you were on a non-SIMD build and are now using AVX2.
I'm using 30.3 b6 and have been for a while.
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Old 2021-05-17, 17:28   #6
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It's running at 2.4 GHz, one thread doing one exponent only, not overclocked or anything.
Ok. If you're running only one test using all 4 cores, it is too slow even now.

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It has 12GB ram, and I don't know the exact configuration of that ram.
Yuck. 12 is such a bad config. Either 8 or 16 would be better. Can you run CPU-Z and find out how many sticks and the size and speed of each stick? It could be that you could get more performance by removing a stick or two.

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Originally Posted by JuanTutors View Post
And about the change, actually I haven't made any changes, and the computer has actually been giving me MORE trouble than usual. (10 minute restart time, glitchy screen effects hinting at a video card issue, etc)
Hmm... It could be that previously the CPU was running at much slower speed (that cpu can throttle down to 1.2 GHz), and a windows update or something caused the speed to increase to 2.4. But with higher speed, there is increased heat which is causing system instability. Just speculating. It might be worth it to open up the PC and dust it out with a blower.
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Old 2021-05-21, 03:47   #7
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... Can you run CPU-Z and find out how many sticks and the size and speed of each stick? ...
Now I am checking all of my computers, but for this computer, it's an i5-7400T at 2.40GHz. Under the SPD tab of CPU-Z, Slot 1 has * GB DD4-2401 (1200 MHz) ram. Slot 3 has 4 GB DDR4-24-1 (1200 MHz) ram. Under the Memory tab of CPU-Z, it says Uncore Frequency 2492.9 MHz varying, and DRAM frequency 1198.0 MHz varying.

And for my laptop it's an i9-9980HK at 2.40GHz with 32 GB Ram, I am running two 100M digit exponents each about 54 ms/iteration. Under the SPD tab of CPU-Z, Slot 1 and 2 each have 16GB DDR4-2667 (1333 MHz) ram. in the Memory tab of CPU-Z, it just says size 32 GB.

In other words, they seem to actually be running at about the same rate, unless I'm not understanding it correctly. Could it be the number of cores I am using? On my PC I am using 4 cores (it's a 4-core proc) with no warning. On my laptop, I am using 8 cores, and Prime95 does give me a warning, but I just clicked yes.
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Old 2021-05-21, 04:34   #8
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Quote:
Originally Posted by JuanTutors View Post
Now I am checking all of my computers, but for this computer, it's an i5-7400T at 2.40GHz. Under the SPD tab of CPU-Z, Slot 1 has * GB DD4-2401 (1200 MHz) ram. Slot 3 has 4 GB DDR4-24-1 (1200 MHz) ram. Under the Memory tab of CPU-Z, it says Uncore Frequency 2492.9 MHz varying, and DRAM frequency 1198.0 MHz varying.
It is possible that since the RAM sticks are mismatching in size, that the CPU is not properly running in dual-channel mode. Is it possible for you to get another 8 or 4 GB stick of DDR4-2400 so that you have two matching ones (either two 8's or two 4's - doesn't matter)?

PS:- I made one mistake - I misread 100M digit PRP test as 100M PRP. So you are not way slower than expected. But still, it is worth trying matching sticks.

EDIT:- If you haven't already done so, it would still be good to open up the PC and blow out the dust.

Last fiddled with by axn on 2021-05-21 at 04:36
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Old 2021-05-21, 05:18   #9
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Ok. I just benchmarked a 100M digit PRP on my i3-8100. Apart from the fixed clock of 3.6 GHz, it is very similar to the 7400T. It is giving iteration time of 26.5ms. Eventhough it is 3.6 GHz, it will be memory bottlenecked. So 37ms for 7400T @ 2.4GHz is in the right ballpark.
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