Lap Top Suddenly 1/4 speed.

petrw1 · 2015-10-26, 21:37

My Laptop crashed this morning. After the restart I fired up Prime95 on my Memory Stick as usual.
A casual glance later noted that the Per Iteration Time for a 60M LL test increased from 0.28Ms to 0.100Ms - 0.130Ms
Task Manager seems normal: says all 4 cores are running near 100% and that Prime95 is using close to 50% if I don't HT and close to 100% if I do.

To attempt to rule out memory contention (i.e. a bad stick) I shut down one worker.. the remaining worker dropped to just under 0.100Ms...still more than 3 times slower than it has been.

Where to start?
Good HW test tools?

Doing 2 X 60M LL tests.

Software Version Windows64,Prime95,v28.6,build 1
Model Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
Features Dual core, hyperthreaded, Prefetch,SSE,SSE2,SSE4,AVX
Speed 2.492 GHz (7.201 GHz P4 effective equivalent)
L1/L2 Cache 32 / 256 KB
Computer Memory 8080 MB configured usage 3000 MB day / 3000 MB night

Prime95 · 2015-10-26, 21:56

Look for tools that will tell you the CPU speed and/or temps.

My bet is thermal throttling. Cause: a dead fan or heat sink no longer properly attached to the CPU. Of course, I could be all wrong.

petrw1 · 2015-10-26, 22:33

Quote:

Originally Posted by Prime95

Look for tools that will tell you the CPU speed and/or temps.

My bet is thermal throttling. Cause: a dead fan or heat sink no longer properly attached to the CPU. Of course, I could be all wrong.

I'm with you on CPU Speed Tools. I found StressMyPc.exe just not sure I am ready to run it or if it is the right one.

CoreTemp have my CPUs at 40 degrees ... not the usual 80 when Prime95 is running.

cuBerBruce · 2015-10-26, 22:36

I would check that you have Windows using a "high performance" power plan. Otherwise it might limit the cpu speed to a rather low speed. Also, if running on battery instead of AC, processor speed might be reduced.

I have a laptop that I thought was getting rather slow LL iteration times when I started running Prime95. I downloaded CPU-Z and found that the processor was running at 800 MHz instead of its rated 2 GHz. I selected "high performance" for the power plan, and that fixed it.

Madpoo · 2015-10-27, 03:55

Quote:

Originally Posted by petrw1

I'm with you on CPU Speed Tools. I found StressMyPc.exe just not sure I am ready to run it or if it is the right one.

CoreTemp have my CPUs at 40 degrees ... not the usual 80 when Prime95 is running.

Try CPU-Z

It updates often enough while running to give you a good idea of the CPU speed at any given time. That's what I used to determine that on a dual socket system, one CPU was doing a higher turbo boost than the other which is why one worker always seemed to be a bit faster.

LaurV · 2015-10-27, 07:51

Quote:

Originally Posted by petrw1

A casual glance later noted that the Per Iteration Time for a 60M LL test increased from 0.28Ms to 0.100Ms - 0.130Ms

Well... that glance was a bit too casual...

retina · 2015-10-27, 10:13

Quote:

Originally Posted by LaurV

Well... that glance was a bit too casual...

Well some laptops can be slow so 280000 seconds might be normal.

LaurV · 2015-10-27, 10:23

Haha, I wasn't thinking to units, I only teased him on the "increase from 0.28 to 0.1" part. Wanted to ask what he did to his laptop that is 3 times faster, maybe I can do it to mine, too...

Madpoo · 2015-10-27, 15:10

Quote:

Originally Posted by LaurV

Haha, I wasn't thinking to units, I only teased him on the "increase from 0.28 to 0.1" part. Wanted to ask what he did to his laptop that is 3 times faster, maybe I can do it to mine, too...

Funny, until you pointed that out I didn't notice either. I *assume* he meant 0.028 to 0.100 ...

I'll be interested to see what speed CPU-Z or whatever shows his system running at. Maybe the BIOS settings reset to defaults and it's now in a friendly power-saving state with turbo disabled and maybe some aggressive c-state throttling.

petrw1 · 2015-10-27, 19:43

This is a work PC... I just reported "general" slowness.
And today I noticed the battery is not charging (even though it is only a year old)
SO they decided my PC was old enough I just get a new one....sadly it is only slightly faster. :(
In the 2 weeks I get to keep both I have time to try CPU-Z

NEW: Intel Core i5-4310U @ 2.00GHz Windows64,v28.6,build 1
OLD: Intel Core i5-2520M @ 2.50GHz Windows64,v28.6,build 1

petrw1 · 2015-10-27, 19:44

Quote:

Originally Posted by Madpoo

Funny, until you pointed that out I didn't notice either. I *assume* he meant 0.028 to 0.100 ....

Yes oops

2015-10-26, 21:37	#1
petrw1 1976 Toyota Corona years forever! "Wayne" Nov 2006 Saskatchewan, Canada 3×5²×71 Posts	Lap Top Suddenly 1/4 speed. My Laptop crashed this morning. After the restart I fired up Prime95 on my Memory Stick as usual. A casual glance later noted that the Per Iteration Time for a 60M LL test increased from 0.28Ms to 0.100Ms - 0.130Ms Task Manager seems normal: says all 4 cores are running near 100% and that Prime95 is using close to 50% if I don't HT and close to 100% if I do. To attempt to rule out memory contention (i.e. a bad stick) I shut down one worker.. the remaining worker dropped to just under 0.100Ms...still more than 3 times slower than it has been. Where to start? Good HW test tools? Doing 2 X 60M LL tests. Software Version Windows64,Prime95,v28.6,build 1 Model Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz Features Dual core, hyperthreaded, Prefetch,SSE,SSE2,SSE4,AVX Speed 2.492 GHz (7.201 GHz P4 effective equivalent) L1/L2 Cache 32 / 256 KB Computer Memory 8080 MB configured usage 3000 MB day / 3000 MB night Last fiddled with by petrw1 on 2015-10-26 at 21:38

2015-10-27, 19:43	#10
petrw1 1976 Toyota Corona years forever! "Wayne" Nov 2006 Saskatchewan, Canada 3·5²·71 Posts	This is a work PC... I just reported "general" slowness. And today I noticed the battery is not charging (even though it is only a year old) SO they decided my PC was old enough I just get a new one....sadly it is only slightly faster. :( In the 2 weeks I get to keep both I have time to try CPU-Z NEW: Intel Core i5-4310U @ 2.00GHz Windows64,v28.6,build 1 OLD: Intel Core i5-2520M @ 2.50GHz Windows64,v28.6,build 1 Last fiddled with by petrw1 on 2015-10-27 at 19:47

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2015-10-26, 21:56	#2
Prime95 P90 years forever! Aug 2002 Yeehaw, FL 2057₁₆ Posts	Look for tools that will tell you the CPU speed and/or temps. My bet is thermal throttling. Cause: a dead fan or heat sink no longer properly attached to the CPU. Of course, I could be all wrong.

2015-10-26, 22:36	#4
cuBerBruce Aug 2012 Mass., USA 2·3·53 Posts	I would check that you have Windows using a "high performance" power plan. Otherwise it might limit the cpu speed to a rather low speed. Also, if running on battery instead of AC, processor speed might be reduced. I have a laptop that I thought was getting rather slow LL iteration times when I started running Prime95. I downloaded CPU-Z and found that the processor was running at 800 MHz instead of its rated 2 GHz. I selected "high performance" for the power plan, and that fixed it.

2015-10-27, 10:23	#8
LaurV Romulan Interpreter "name field" Jun 2011 Thailand 41·251 Posts	Haha, I wasn't thinking to units, I only teased him on the "increase from 0.28 to 0.1" part. Wanted to ask what he did to his laptop that is 3 times faster, maybe I can do it to mine, too...