CPU at 180% :s

2011-08-18, 15:24

I have searched this and read some of the overheating problems, this seems a bit different.
Got a macbook pro (i know - a mac - not the question..), 2.26ghz dual core, 2gb ram, about 18 months old running 10.5.8

As soon as I start running prime95 activity monitor claims the cpu is running at 180%, the fans start up and within 1 minute i can feel the shell heating up. % minutes too hot to hold.
I haven't even bothered checking the CPU speed, I'm not comfortable running it like that (unless that's normal..?)

I understand that prime95 is designed to run at the computers max cpu speed but 180% seems wrong? unless it means 90% per core?
Either way it's overheating so is there a way to limit the programs cpu usage (to say 80%).
I know that I can set it up so it runs in cycles (eg 1 second on 1 second off) but I imagine there is a way to limit its CPU allowance, or stop it from going so high?

Would love to be a part of the cause but I'm not frying my laptop for it...

-I'm a poor uni student and the laptop was a gift, I have no desktop :(
and I know...apple...

thanks

firejuggler · 2011-08-18, 17:37

You can limit prime95 to work with only one CPU.
If the interface is the same as the windows one, go to Test, Worker Windows, then in the windows, set 1 for Number of windows to run and CPU to use/ this way, it will only use one CPU to the max, and your laptop wont heat as much.

sichase · 2011-08-18, 19:27

Quote:

Originally Posted by Unregistered

I have searched this and read some of the overheating problems, this seems a bit different.
Got a macbook pro (i know - a mac - not the question..), 2.26ghz dual core, 2gb ram, about 18 months old running 10.5.8

As soon as I start running prime95 activity monitor claims the cpu is running at 180%, the fans start up and within 1 minute i can feel the shell heating up. % minutes too hot to hold.
I haven't even bothered checking the CPU speed, I'm not comfortable running it like that (unless that's normal..?)

I understand that prime95 is designed to run at the computers max cpu speed but 180% seems wrong? unless it means 90% per core?
Either way it's overheating so is there a way to limit the programs cpu usage (to say 80%).
I know that I can set it up so it runs in cycles (eg 1 second on 1 second off) but I imagine there is a way to limit its CPU allowance, or stop it from going so high?

Would love to be a part of the cause but I'm not frying my laptop for it...

-I'm a poor uni student and the laptop was a gift, I have no desktop :(
and I know...apple...

thanks

180% _does_ mean 90% per core. Your laptop is designed to run at 100% per core indefinitely, so provided that you place it such that it can properly ventilate itself, you should have no problem running full-out. And the priority of Prime95 is set such that anytime you try to do anything else, your new task will immediately get CPU attention. So you should see no impact on your other work from running Prime95.

Of course, if you don't like the fan noise or don't want to pay for the power, you can do as the previous poster suggested and limit Prime95 to a single core. But I expect that even that will drive your fan to run full time.

--Scott

Brain · 2011-08-18, 20:01

See undoc.txt:

Code:

If you are running on a laptop or in a hot room and you want to slow the
program down to reduce heat, then you can add this line to prime.txt:
    Throttle=n
where n is the percentage of time the program should run.  For example,
Throttle=40 means the program will run 40% and be idle 60% of the time.

Christenson · 2011-08-18, 21:52

There's another good use for the "Throttle" setting...

Opera (or maybe it's windows) seems to have a step in the download process that runs at minimum priority. Setting "Throttle=95" for 95% run-time greatly improves the useability of the machine. This has also saved my ability to run at all on my wife's machine, which runs windows XP.

And no, we don't know "Apple"...it's fine compute hardware...with the odd property of not having half the virus and crash problems of windows, and generally being able to get the work done.

But if you can't replace the laptop, you do want to run it cool...all laptops I am familiar with have had much shorter lives than their contemporary desktops. Take care.

Uncwilly · 2011-08-18, 23:49

Trial factoring should also produce less heat.

2011-08-19, 16:40

@christenson
I'm sure you understand what you mean about apple, very difficult (and overpriced) to replace individual components (via apple), though I guess you can say the same about any laptop.
And I do want it to run cool and last as long as possible, I'm not in a situation to replace it anytime soon.

I've read about the throttle=n setting but to be honest i don't think that solution is any better.
I'm no expert in computer hardware but I know with most other delicate hardware switching from 100% consumption to 10% then back to 100% every second is not healthy.
I tried running one core but still it gets to hot for to sit on my lap or anything (yes I know that it's not ideal for heat ventilation but it's regardless of position.

I guess I should've just asked does anyone know a way to limit the programs access to the cpu? must be some freeware out there?

retina · 2011-08-19, 17:07

Quote:

Originally Posted by Unregistered

I'm no expert in computer hardware but I know with most other delicate hardware switching from 100% consumption to 10% then back to 100% every second is not healthy.

Thermal cycling. It is not a good thing for the longevity of anything, whether it be electronic or not. CPU chips can heat up very quickly, so one second bursts can still cause considerable thermal changes. Cycle that 86400 times per day and the thing will crack apart in short order.

Christenson · 2011-08-19, 22:02

That's a perfectly good scientific argument for P95 to figure out how to increase the frequency of his CPU-throttling behavior. I wish I could commit to figuring that out from the source code; all I can say is that if you read it, you may be able to figure it out.

One approach I might try is to force P95 to print on EVERY iteration -- and let the act of printing effectively throttle the CPU usage as P95 is forced to wait on I/O to the graphics system.

But in the OP's shoes, I would be very reluctant to be doing the experiments, since he has no good way of replacing anything if it goes bad on him.

2011-08-20, 23:49

Quote:

Originally Posted by Christenson

But in the OP's shoes, I would be very reluctant to be doing the experiments, since he has no good way of replacing anything if it goes bad on him.

Unfortunately this is what I've decided. Maybe when I get a desktop set up I will run 24/7 but as this is my only computer I don't really want to fry it.

Thanks for the help everyone, hopefully I'll join the hunt again soon

jasong · 2011-08-21, 14:16

Well, considering the fact that any Linux program that has source code available can be compiled to run on Apple, it's simply a matter of finding someone willing to fight with the compiling programs to get it done. Might be worthwhile considering how much Apple has increased it's market share.

And, yes, I know fighting the compiling programs is an additional problem, not just finding someone willing to run a program lickety-split.

2011-08-18, 15:24	#1
Unregistered 7254₈ Posts	CPU at 180% :s I have searched this and read some of the overheating problems, this seems a bit different. Got a macbook pro (i know - a mac - not the question..), 2.26ghz dual core, 2gb ram, about 18 months old running 10.5.8 As soon as I start running prime95 activity monitor claims the cpu is running at 180%, the fans start up and within 1 minute i can feel the shell heating up. % minutes too hot to hold. I haven't even bothered checking the CPU speed, I'm not comfortable running it like that (unless that's normal..?) I understand that prime95 is designed to run at the computers max cpu speed but 180% seems wrong? unless it means 90% per core? Either way it's overheating so is there a way to limit the programs cpu usage (to say 80%). I know that I can set it up so it runs in cycles (eg 1 second on 1 second off) but I imagine there is a way to limit its CPU allowance, or stop it from going so high? Would love to be a part of the cause but I'm not frying my laptop for it... -I'm a poor uni student and the laptop was a gift, I have no desktop :( and I know...apple... thanks

2011-08-18, 17:37	#2
firejuggler "Vincent" Apr 2010 Over the rainbow 2³×5×73 Posts	You can limit prime95 to work with only one CPU. If the interface is the same as the windows one, go to Test, Worker Windows, then in the windows, set 1 for Number of windows to run and CPU to use/ this way, it will only use one CPU to the max, and your laptop wont heat as much.

2011-08-18, 21:52	#5
Christenson Dec 2010 Monticello 5×359 Posts	There's another good use for the "Throttle" setting... Opera (or maybe it's windows) seems to have a step in the download process that runs at minimum priority. Setting "Throttle=95" for 95% run-time greatly improves the useability of the machine. This has also saved my ability to run at all on my wife's machine, which runs windows XP. And no, we don't know "Apple"...it's fine compute hardware...with the odd property of not having half the virus and crash problems of windows, and generally being able to get the work done. But if you can't replace the laptop, you do want to run it cool...all laptops I am familiar with have had much shorter lives than their contemporary desktops. Take care.

2011-08-18, 23:49	#6
Uncwilly 6809 > 6502 """"""""""""""""""" Aug 2003 101×103 Posts 2²·2,767 Posts	Trial factoring should also produce less heat.

2011-08-19, 16:40	#7
Unregistered 1001000011001₂ Posts	@christenson I'm sure you understand what you mean about apple, very difficult (and overpriced) to replace individual components (via apple), though I guess you can say the same about any laptop. And I do want it to run cool and last as long as possible, I'm not in a situation to replace it anytime soon. I've read about the throttle=n setting but to be honest i don't think that solution is any better. I'm no expert in computer hardware but I know with most other delicate hardware switching from 100% consumption to 10% then back to 100% every second is not healthy. I tried running one core but still it gets to hot for to sit on my lap or anything (yes I know that it's not ideal for heat ventilation but it's regardless of position. I guess I should've just asked does anyone know a way to limit the programs access to the cpu? must be some freeware out there?

2011-08-19, 22:02	#9
Christenson Dec 2010 Monticello 5·359 Posts	That's a perfectly good scientific argument for P95 to figure out how to increase the frequency of his CPU-throttling behavior. I wish I could commit to figuring that out from the source code; all I can say is that if you read it, you may be able to figure it out. One approach I might try is to force P95 to print on EVERY iteration -- and let the act of printing effectively throttle the CPU usage as P95 is forced to wait on I/O to the graphics system. But in the OP's shoes, I would be very reluctant to be doing the experiments, since he has no good way of replacing anything if it goes bad on him.

2011-08-21, 14:16	#11
jasong "Jason Goatcher" Mar 2005 3×7×167 Posts	Well, considering the fact that any Linux program that has source code available can be compiled to run on Apple, it's simply a matter of finding someone willing to fight with the compiling programs to get it done. Might be worthwhile considering how much Apple has increased it's market share. And, yes, I know fighting the compiling programs is an additional problem, not just finding someone willing to run a program lickety-split.