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Old 2016-07-26, 11:38   #1
Jul 2016

2·3 Posts
Unhappy Set affinity does not work


sorry for the "newbie" question, but my Google skills did not find an answer

I have Prime95 v28.7 running on a Lenovo P700 under Windows 7 pro. There are 2 cpus with 10 cores each plus hyperthreading in the Computer.
Now I'd like to restrict prime to one socket so I can use the other for my daily work.
If I use the Standard "local.txt", the tool tells me "Setting affinity to run on any Logical CPU".
I tried add adding the entry "AffinityScramble2=132457689A0BCEDFGIHJ" entry, but with that the program crashes.
Now I am lost. What should I have done?

Guenter from Germany
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Old 2016-07-26, 13:52   #2
GP2's Avatar
Sep 2003

258710 Posts

First of all, you should update to v28.9, there is an important improvement.

You can delete your old prime.txt and local.txt and start over, to clear out any
mistaken modifications.

If you choose to edit your existing files instead, then in your local.txt file, you should find a lines similar to:


If there is no WorkerThreads line, it defaults to 1.

The above is for a computer with 8 cores, where two exponents are being tested simultaneously (i.e., two "workers"), with each test using 4 cores (one main thread and three helper threads).

Note: To make any adjustment, you must first stop the program, then edit the file, then restart the program.

Last fiddled with by GP2 on 2016-07-26 at 13:56
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Old 2016-07-27, 05:19   #3
Jul 2016

1102 Posts

Hi GP2,

thanks for your info. I did get the latest version and had a look at your suggested options.
Unfortunately, this does not change the "run worker on any logical CPU" problem. Where can I control the core on which the worker is running?

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Old 2016-07-27, 05:26   #4
Jul 2016

68 Posts


the new version seems to be much better in clinging to the core :)

I still have the "running on any logical cpu" message, but using Task manager I can see that only the first CPU is used and all cores on it (including the hyperthreading) are running on 100%, while all cores of the second CPU are idling.

Well done!

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