Disabling 1 core in a dual core processor

[kaos1911]

Hi,
The short story is that I need to know if there is anyway to turn off one core in a dual core processor.

The longer story is that a while ago I decided to upgrade my amd processor from a single core 3500 to a dual core 3800. It worked fine but I eventualy realised that my motherboard didn't support dual core processors and It was only using one core. However seeing as it was still faster then my single core I decided to leave it in and deal with it later (as and when funds permited a more extensive upgrade).

Now recently my PC was having some issues, probably caused by a virus so I sent it off to a PC shop to get fixed. It came back seemingly working fine but it crashed far more reguarly. Eventualy I traced It down and I think the problem is the PC shop somehow managed to enable both cores, so whenever a process is pased from one core to another, such as opening up a different program when one is already running, my computer crashes and restarts.

As a tempory fix I have just turned off the second processor from working with various programs by setting the affinity in task manager which has made things fairly stable for the moment, but I would like to know if there is a more permenant fix I have had a brief look in the bios but there doesn't seem to be anything there (and I'm also not entirely sure what to look for)

I would call up the shop and ask what they did but as sod's law would have it they are closed for the next few days and I need to have my PC working sooner rather then later.

Any help would be very much appreciated
thanks

[MadduckUK]

whats the motherboard?

[kaos1911]

its an nvidia n-force4 running a phoenix bios

[Fraz]

Have you considered seeing if there is a BIOS update for your mobo so that it will support both cores properly?

If not then...:

It sounds like the PC shop updated your HAL so that it is now running as an ACPI Multiprocessor PC. You need to roll back the driver to being a uniprocessor PC. Try the following at your own risk:

1) Start device manager.
2) In device manager expand 'Computer'.
3) Under Computer you should see the currently installed 'HAL' information "Advanced Configuration and Power Interface (ACPI) Multiprocessor PC", or some such. Double click on this.
4) Click on the driver tab and try the "Roll back driver" option.

[MadduckUK]

yep, almost certainly only a BIOS update from dual cores working on it

a 3800 using one core wouldn't be as fast as a 3500 btw :/

[kaos1911]

hmm I'm not sure it will I'm already running the most up to date bios as found here:

http://www.ecs.com.tw/ECSWebSite/Dow...nuID=6&LanID=0

Perhaps I should have gone into more detail its a Nforce4-A939 designed for atalon's and FX's not dual cores, (its 2005 so before dual cores really came onto the scene)

[kaos1911]

Also I tried rolling back the driver and there was no previous driver (although considering the PC shop reinstalled windows this is perhaps not that unusual). I seem to recal reading about a program which could forcibly change the HAL, do you think it might work in this situation?

[MadduckUK]

BIOS Name BIOS for NFORCE4-A939 (PCB:1.0)
Version 1.1K
Release Date 2006/08/10
Update Description -Fixed Use USB storage large files size copying to HDD or USB HDD failed issue
-Fixed AMD Cool 'n' Quiet function fail on WIN2K OS
-Update to RAID ROM V5.5
-Support FX-60 VID for 1.35v CPU
-Fixup system will hang while Setup SATA RAID Enabled
-Support AMD FX-60 Dual Core processors
-Update BIOS for AMD new E4 CPU
-Fix Patch PCI device just need option resource cannot work
-Support Dual Core 3800+ CPU
-Dual Core CPU Support
-Support Rev.E3 CPU

[kaos1911]

Yep that's the one I have instaled currently and the issues not with the support, The system reads that I have a 3800 installed when it boots and in the device manager but it still seems to crash whenever I try to run more then one program.

This is what it comes up in system information:
BIOS Version/Date Phoenix Technologies, LTD 6.00 PG, 30/06/2006

[kaos1911]

hmm thats interesting my system reads the bios as:

BIOS Version/Date Phoenix Technologies, LTD 6.00 PG, 30/06/2006

whereas the one on the site is dated:

Release Date 2006/08/10

I double checked its the same version just a difference in release date and completion date.

[strike-down]

well if it works, then yes otherwise you could try reinstalling drivers in windows.

[kaos1911]

Ok I think I've fixed it, so just to close this one up and for anyone else who might find themselves with the same problem:

Start device manager.
In device manager expand 'Computer'
Under Computer you should see the currently installed 'HAL' information
"Multiprocessor PC"
Right click the (ACPI)PC device and chose 'Update Driver'
Select the (Advance) radio button in the Hardware Update Wizard and click
next.
Select 'Don't search. I will choose the driver to install' and click next.
Make sure the "Show compatible hardware" check box is checked on the next
screen
Select the correct HAL for your system type and follow the instruction from
the wizard to complete the install.

In this case I updated it from multiprocessor to just acpi and my system seems stable now so I think that was the solution.

Thanks for everyone who helped with advice!