FX-55 and multi-tasking.

[clentz]

I'm in the process of stress testing (burning in) my new system. Prime95 runs perfect all night long on it?s own, but as soon as I start seti@home, or 3DMark, prime95 seems to either stop computing or it simply slow way, way down.

I'm thinking/hoping that this is just single CPU behavior in general, because my systems in the past were all Intel and only tested with prime95, and my very last system, which would run prime95 and seti@home at the same time was a hyper-threading cpu.

I would still think that any CPU now-a-days would be able to multi-task both programs and still compute prime95, but like I said, maybe it is, it's just computing very, very slowly.

Thank you for any help/thoughts on the matter.

Charles

 

[zakee00]

i noticed that my 64 3000+ ins't the best multitasker, either. I have a feeling that Intel P4's are much better.

 

[Vee]

You need to consider Windows instead of your CPU, because it's Windows that shedules the threads.
And yes, some P4s, the ht ones, often take priority glitches in their stride, since they work on two threads.
But proper multitasking should be achievable with single threaded CPUs, P4s and AMD as well.

(In order to let processes with equal priorities get equal share of the CPU, you need to set
This Computer->properties->advanced->performance->settings->advanced... (I think) ...to something like server/background (differs on Windows version)

This is in paranthesis, since this is not really what you want however, since you normally still would want to give priority to the active window's process. It should also not have any effect on the following. It's just included for your information.)


Anyway, check the priorities for SETI and Prime95. Taskmanager->Processes.

I normally run SETI at 'idle' which means it only runs on 'low' basic priority.
Prime95 also runs at 'low'.
(SETI and Prime have their own internal background thread priorities, that are based on this 'basic' setting. So one does not really always know exactly what will happen if one changes anything.)

Check that you run SETI at 'idle' setting (in the SETI driver).
Check that you run Prime95 torture test at "small FFT" or "in-place...", otherwise it won't use up available CPU capacity.

Now SETI and Prime95 should share up CPU, roughly 50-50, visable in the taskmanager.
Do they not?

 

[clentz]

What do you mean by the "SETI driver"?

I rebooted, SETI is set to load when windows starts. I double clicked it in the tray to maximize it & start it up. I checked TaskManager, it was set at low. I then started Prime95, started a touture test. SETI is mostly at 99, Prime is mostly at 00. Every 10 or so seconds, I get 06 for Prime and 94 for SETI. I tried torture test twice with in-place the first time, and FFt this last time.

Prime hasn't finished a single test yet while SETI is running.

 

[Vee]

Originally posted by: clentz
What do you mean by the "SETI driver"?

Never mind. I assume you run a different version of SETI. Doesn't matter anyway, I think.

I rebooted, SETI is set to load when windows starts. I double clicked it in the tray to maximize it & start it up. I checked TaskManager, it was set at low. I then started Prime95, started a touture test. SETI is mostly at 99, Prime is mostly at 00. Every 10 or so seconds, I get 06 for Prime and 94 for SETI. I tried torture test twice with in-place the first time, and FFt this last time.

Prime hasn't finished a single test yet while SETI is running.

"Interesting"

Ok, what happens if you raise basic priority to 'lower than normal' or 'normal'?

But actually, the difference is too large anyway. It's more as if Prime95 can't use up CPU power, than running at lower pri. How much memory do they use? I have 8MB for Prime95 and 16MB for SETI.
(And I'm currently still geographically distanced from my A64s, so I'm not actually - yet - able to verify this on AMD64.)

 

[Megatomic]

When I try to run a blended Prime95 test on my system, Prime95 takes up 1.5GB of memory and gets 0% CPU. Not one FFT is completed. I think there is a problem with Prime95 that went unexposed until I got my system running .

Seriously, this is repeatable and I can take screenshots later if you all would like to see this.

 

[Slaimus]

Prime's processing threads are purposely written to run at lower priority. The program is designed to run in the background and use up any excess processing power.

 

[clentz]

That makes sense, and it also makes sense that prime would use the hyper-threading feature when I had them both running on my Intel HT system. With only one of the two programs, the Intel system would show overall CPU usage at 50% and one of the virtual processors at 100%. With both running, it was at 100%, 100%.

Learn something new everyday; Learned today that Prime95 uses what ever cpu cycles are left over. So if I use a program besides SETI, a program that didn't use 100% cpu, 100% of the time, Prime would finish some calculations.

Thank you all for your help, and for my improved computer knowledge.

 

[Megatomic]

Originally posted by: Slaimus
Prime's processing threads are purposely written to run at lower priority. The program is designed to run in the background and use up any excess processing power.

In my case, with Prime95 at 0% CPU System Idle had 99% CPU (on average). I know how Prime95 works, I used it a lot when I was getting my XP overclocks right. It's not acting right for me anymore.

 

[LifeStealer]

Prime95 doesn't really care for A64 builds for some reason. Alot of people have trouble running it, I think its more of a windows problem that anything else.