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My CPU usage never goes above 50%

S

Shadmere

Member
I've got an Opteron 165. I installed the dual core drivers. I haven't installed the hotfix, because everything I've read says that the hotfix only helps with problems encountered with Cool 'n' Quiet, and I don't have that activated.

Now, let's say I run Prime95. It will immediately jump up to 50% of my CPU usage. If I set the affinity to Core 0, it stays at 50%. It I set the affinity to core 1, it stays at 50%. If I set the affinity to both cores, it stays at 50%.

Now let's say I run another instance of Prime95. It will hover between 3% and 6%. It will never go above 7 or 8%. If I set one instance to core 0, and one to core 1, the first instance that I ran will stay at 50% and the second instance will hover around 5%. If I switch the instances' affinities, the usages stay the same. (The first instance stays at 50%, the second stays at 5% or so. Even when put on a different core.)

Is this messed up? I should think that if two instances were running, one on each core, they would use about the same amount of CPU?

I can easily get 50% usage from either core, but I can't get it from both?

What's wrong?

Thanks.
 
Sounds like you aren't setting it up properly. You need to have the affinity set when starting it up. Make 2 shortcuts to prime95.exe on your desktop. On the first one, right click, and click properties. In the target section, put -a0 at the end. Do the same for the second shortcut but put -a1. Then start each one.
 
Before or after the quotes in the target section? After, I guess, since it says that in front of the quotes is invalid.

I put it after them and ran it. The first instance is at 50%, the second is at 1%. When I right click on them and go to 'set affinities,' both core 0 and core 1 are checked.
 
This is the EXACT problem I had and I never figured out how to get prime95 to run on both cores of my 165. I simply downloaded Stress Prime 2004 which is the exact same thing as prime95 but with a better GUI. I had no issues running two copies of that and getting too 100% utilization.

Give that a try and let us know if it works.

-spike
 
I downloaded Stress Prime 2004.

I ran two instances. I chose 'core 0' on one, and 'core 1' on the other.

I hit 'start' on both.

The first instance immediately went to 50%. The second was at 5 or 6%, then slowly worked its way up to 50% as well.

It then dropped back down into the 20s. Then back to 5%. Then back up to 50%. Then back down to hover aroudn 2-3% for the next five minutes or so.

The first instance stayed at 50% the whole time. When I ended the first instance, the second instance immediately shot up to 50% and stayed there.
 
50% on a dual-processor computer = 100% on a processor. Perhaps there's no problem?

You can also change the Performance/View/CPU History/One Graph per CPU to see the load and distribution.
 
Originally posted by: Shadmere
I downloaded Stress Prime 2004.

I ran two instances. I chose 'core 0' on one, and 'core 1' on the other.

I hit 'start' on both.

The first instance immediately went to 50%. The second was at 5 or 6%, then slowly worked its way up to 50% as well.

It then dropped back down into the 20s. Then back to 5%. Then back up to 50%. Then back down to hover aroudn 2-3% for the next five minutes or so.

The first instance stayed at 50% the whole time. When I ended the first instance, the second instance immediately shot up to 50% and stayed there.
Click to expand...

Man, I am not sure what is going on. I put the program into two seperate directories and started each from it's own dir. Not sure if that makes any difference but that is what I did to get it to work. Other than that I changed nothing in the setup...
 
Originally posted by: Madwand1
50% on a dual-processor computer = 100% on a processor. Perhaps there's no problem?
You can also change the Performance/View/CPU History/One Graph per CPU to see the load and distribution.
Click to expand...

That means 100% on ONE processor, not both. In order to properly stress a dual core (ie test a overclock) you need to run both cores at max.

-spike
 
OK, my next guess is that too much RAM is being used by the two instances combined. When it's running out of RAM, it's losing CPU cycles. Then try reducing the RAM usage of at least 1 instance.
 
Running small ffts on both instances pushed my CPU usage up to 100%.

I can't figure out how to run large ffts and do that.
 
No, I really did explain this. (I just checked my previous post and made sure.)

Two instances are running.

One will go to 50%. The other will stay at like 5%, and never once go above 6 or 7%.

If I run small ffts, both will run at 50%, like they should.q
 
Originally posted by: Shadmere
No, I really did explain this. (I just checked my previous post and made sure.)

Two instances are running.

One will go to 50%. The other will stay at like 5%, and never once go above 6 or 7%.

If I run small ffts, both will run at 50%, like they should.q
Click to expand...

No, if you run two instances of small FFTs and have affinity set correctly, then each should hit 100% usage.
 
That other guy just said that on a dual core, each instance will hit 50%. Totalling 100%.

How could two instances both run at 100% usage? That gives the computer 200% power.

When I run large ffts, I can only get 50% out of one of them, and the other won't go over 10%.

I am glad that I'm getting so many opposing answers though. Assuring. =Þ
 
Originally posted by: aka1nas
Originally posted by: Shadmere
No, I really did explain this. (I just checked my previous post and made sure.)

Two instances are running.

One will go to 50%. The other will stay at like 5%, and never once go above 6 or 7%.

If I run small ffts, both will run at 50%, like they should.q
Click to expand...

No, if you run two instances of small FFTs and have affinity set correctly, then each should hit 100% usage.
Click to expand...

He is saying that each app reports 50% cpu total cpu usage, I.E> how windows reports it


 
Originally posted by: aka1nas
Originally posted by: Shadmere
No, I really did explain this. (I just checked my previous post and made sure.)

Two instances are running.

One will go to 50%. The other will stay at like 5%, and never once go above 6 or 7%.

If I run small ffts, both will run at 50%, like they should.q
Click to expand...

No, if you run two instances of small FFTs and have affinity set correctly, then each should hit 100% usage.
Click to expand...

Ok, just to clarify, if you select one graph per cpu in task manager and are running 2 instances of prime, both CPU graphs are fully utilized or are they each at 50%?

Edit: made the post a bit less confusing.🙂
 
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