I wanted to upgrade some machines and mistakenly bought mobile AMD 3500 (socket 754) CPUs instead of standard desktop CPUs.
I only realized this after plugging them in and started the machine (though I did have to make some adjustments to get the fan to sit properly - which I did find odd at the time) and finding that they were running at 800 mhz instead of the 2.2 ghz their desktop counterparts would run at.
I did the upgrade in the hope of improving frame rates for some of the games I play but after upgrading from my AMD 1800 to this mobile 3500 frame rates actually went down.
My understanding is that mobile chips simply ramp up and down as required of them under load although that doesn't seem to be the case, as in my game it never 'ramped up'.
Is there a way to force them to run at the full speed always? What other differences are there?
It will probably never work right in your desktop board only thing i could suggest is go into bios turn off cool and quiet and see if you can maybe raise the clock speed not sure how well it will handle that i have no experience with mobile cpus in a desktop setting.
Does your motherboard have BIOS support for a mobile variation of the processor? That is most likely the cause of the problem.
I know some socket 754 desktops could use the mobile processors, I purchased a socket 754 Sempron/mobo combo from the egg years ago for my sister and was surprised to find out it was a mobile varient of the processor.
1] BIOS support - Go to Motherboard vendors website and check for supported processors. They release upgrades to BIOS for supporting newer processors (processors newer than the board which could work fine with an upgrade).
2] OS like XP mostly increases frequency of the processor if its under load, unless you have enabled MAX battery in power options. When you use MAX battery the OS tries to conserve power by never increasing the frequency of processor.
3] Incorrect FSB settings in BIOS.
4] SAAIELLO has suggested to "turn off cool and quiet". This could be one of the reasons. Many BIOS have similar settings, which could lock the processor frequency at the lowest and make it run Cool and Quiet....