How disable one CPU core?

[killeen]

I have tried several games so far, and came to the conclusion that most of the older ones have problems with the dual core cpu.

I was wondering how you can disable one of the cores in the dual core processor.
I heard that this feature is supported by intel, but I have no idea how to do it and I can't find a how-to or something like that.

any ideas?

[killeen]

I finally figured it out myself:

You need to right click on "My Computer" -> Properties -> Advanced -> Startup & Recovery;

There, you will find a button named "edit" - by pressing it you can edit the Windows Boot.ini file manually.

at the end of the line add the following code:

/numproc=1

save the Boot.ini file and reboot

Your Windows XP Install will now only use one Processor Core.

The games which I had problems with before are now fully functional.

[Cynic821]

Thats a very good tip, keep bumped ?

[ecchi]

that's a little drastic measure to completely disable 1 cpu (which could benefit usage in SMP apps).

Try to launch the game, CTRL-Tab or ALT+CTRL+DEL to get to the task manager, select the game from the process list, right-click it and click Set Affinity. This will have both cores checked - un-check one. Close Task Manager/return to the game.

[killeen]

I have run the 3DMark03 Benchmark to compare gaming performance between 1 and 2 processor cores.

Here are the results: (512 MB of RAM)

3DMark03:

1 Core: 1538 Points
2 Cores: 1679 Points

[adurdin]

Imagecfg http://www.robpol86.com/Pages/imagecfg.php is a tool that can permanently set the affinity of an .exe. I successfully used it to get Thief I and II to play on my iMac -- they would freeze without it.

[chrisp]

adurdin, thanks for that hint! It allowed me to get Perimeter and Painkiller running properly.

[koltroll]

Would be nice if you just wrote down all games that need this, in order to work.
thanks.

/Robert/Koltroll

[Yixian]

Would be nice if you just wrote down all games that need this, in order to work.
thanks.

/Robert/Koltroll

There'll be thousands of them. Hopefully Apple will include an auto-core-shutdown type feature in Leopard that will turn off one processor whenever needed, and flick it back on afterward.

[OptimismPrime]

And how would the OS know what the apropriate time is to shut down one core?
Magic 8 Ball? A.I.?

Hello Dave, i sense you want to play an old Game Dave, i will now shut down one CPU core for you... :p

Na, seriously, a program that sets CPU affinity is the right thing.....
Multicore or- CPU system are there so they can balance the load between their logical Processors.

If a program gets confused and doesn't work if it is presented with 2, let it only be presented with 1....but don't criple the performance of everything running in the background while you play a game, just because it's an "older model".

And besides, in the Dev Tools there is a mini app that lets you disable and enable the 2nd core on the fly..... with some programs running that even kernel panics OSX......

As for Windows.....no such tool i'd know of yet.
And the solution for permanently setting CPU affinity of programs is a FAR better solution anyway.