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Old 2007-04-12, 05:14   #1
ewergela
 

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Default Core 2 duo

I assume that the Core 2 duo processor can run two instances successfully of prime95. I also assume that the benchmarks for the Core 2 duo are based on one instance of prime95, but to get the most out of the processor two instances would be better. Can anyone confirm this?
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Old 2007-04-12, 12:45   #2
rx7350
 
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You are correct - running two instances of PRIME95 on a dual-core cpu, one instance in each core, gets more work done than running one instance, and only increases iteration times slightly for both. See the readme file in the PRIME95 folder for info on how to run two instances. Make sure that the affinity for one instance is set to cpu0, and the other instance set to cpu1.
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Old 2007-10-07, 14:34   #3
Grant
 
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Default changing affinity

is setting affinnity the same as using the command line -a1?

I tried setting affinity for my E6600 in task manager but it will not let me change affinity for a 'system program' which Prime 95 is now that it 'boots at start up'

I think it may be "easier" to just go to version 25.3 instead of 24.14 and run a single instance using 2 cores.

I understand that 25.3 is still beta?
Is it ok to use this now for real work?

Last fiddled with by Grant on 2007-10-07 at 14:57
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Old 2007-10-07, 15:29   #4
Mr. P-1
 
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Quote:
Originally Posted by Grant View Post
is setting affinnity the same as using the command line -a1?
No, but you need to use -a1 to run a second instance in the same directory.

To set affinity choose Advanced/Affinity. You will need to do this for both instances, setting a different affinity for each one. You don't need to do anything in the task manager in XP. (I don't know about other Windows versions.)

Also, if you're doing first-time tests with both cores, and you're prepared to allocate extra memory for stage 2 of P-1 testing, Then give the two instances non-overlapping time windows for this, unless you have heaps of memory and can afford to allow two stage 2s to proceed at the same time.

Quote:
I think it may be "easier" to just go to version 25.3 instead of 24.14 and run a single instance using 2 cores.

I understand that 25.3 is still beta?
Yes.

Quote:
Is it ok to use this now for real work?
In my opinion, it isn't. Stick to 24.14
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Old 2007-10-07, 15:48   #5
Grant
 
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Thaks p-1

I still do not understand how to use the command line -a1 step
how do I create another instance of prime95?
A detailed step by step would be most appreciated

Also, my wife just loves your avatar.
She plays alot of tennis

Last fiddled with by Grant on 2007-10-07 at 15:49
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Old 2007-10-08, 13:34   #6
Grant
 
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Default I did it

Hi P -1

sorry to have bothered you with this question.

I took the easy way to create a second instance and just copied Prime 95 into a separate directory and changed the affinity on both copies

Thanks
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Old 2007-10-08, 15:08   #7
Grant
 
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Default more info

When the second instance started it did a self-test, which it failed.
This surprised me since I had recently did a 36hour torture test on my system, which it passed.

I assume that the reason it failed because I was also running my original copy of Prime on the other Core??
Anyway, I lowerd by overclock from 3.2 to 3.15 and it passed the self test.
Then lowered my overclock to 3.1

It is all working fine now.

I chnaged the name of Prime95 to Prime95a for the second instance so I could keep track of which one I was looking at.

Interestingly, this second instance still shows as Prime95 in its window but shows as Prime95a in Task Manager.

Also the second instance does not start at startup even though I have "start at bootup" in the options dialog??
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Old 2007-10-08, 15:47   #8
Cruelty
 
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I prefer running Prime95 instances from separate directories rather than using -ax switch
Previously did you run stress test on both CPU cores? Which tests did you choose for your configuration then? Look here for some hints.
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Old 2007-10-08, 15:59   #9
Mr. P-1
 
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You can keep it all in the same directory by (on an XP machine) clicking Start/Run and entering C:\path\to\prime95\prime95 -a1

Quote:
Originally Posted by Grant View Post
Also the second instance does not start at startup even though I have "start at bootup" in the options dialog??
Perhaps this is because you changed the name.
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Old 2007-10-08, 16:35   #10
Grant
 
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Hi Mr P - 1

Thanks for the suggestion.

I changed the name back to Prime95 and rebooted.
The second instance did not start, the first instance did

The first instance shows as a 'system' app
the second as a 'Grant' app in Task manager

??

Grant
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Old 2007-10-09, 06:29   #11
Mr. P-1
 
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Quote:
Originally Posted by Grant View Post
Hi Mr P - 1

Thanks for the suggestion.

I changed the name back to Prime95 and rebooted.
The second instance did not start, the first instance did

The first instance shows as a 'system' app
the second as a 'Grant' app in Task manager

??

Grant
I don't use Windows, so I'm not sure, but I would guess that "Grant" is your user name, and it's just saying that the app belongs to you.

Try clearing and re-setting 'start at boot up'.
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