My CPU speed doesn't show correctly in Sandra

I have a Socket 478 P4 2.53 Ghz CPU. Sandra Lite shows it running at a speed of 1.91 Ghz. I have an Asus P4T533-C motherboard running at the defaults. Why would this be?
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  1. Make sure the fsb is set to 133 and not 100 mhz.
    You can do that in the bios.
  2. Quote:
    Make sure the fsb is set to 133 and not 100 mhz.
    You can do that in the bios.

    Ya, I had the same problem when I first put my comp together, altho I had to change a jumper in the mobo to change the FSB
  3. Yep, that's almost certainly the problem.

    133Mhz FSB times a multiplier of 19 equals 2.53Ghz
    100Mhz FSB times a multiplier of 19 equals 1.90Ghz

  4. Again: FSB.
  5. Thanks for pointing me in the right direction! I checked, and the FSB was set wrong. In fact, the processor speed option was set to manual, and the FSB set to 100/ something. When I changed the processor speed to 2.53mhz, it changed the FSB. The only problem now is that it won't load the OS. It boots and goes through POST, but when it gets to the OS load, it just sits there with a dark screen.

    Any ideas? It's an Asus P4T533-C mobo with the latest bios (considering this is a 4 year old board).
  6. OS loads fine at 1.9 but not at 2.53.
    What are the fsb and multiplyer set at now.
    What speed memory do you have. You should have 533 Mhz memory.
  7. I just checked and it looked like setting the mobo to defaults may have fixed it, oddly enough. Sandra now shows the CPU at 2.54 and the FSB at 534. I have Rambus memory (I know, it's like I bought a beta-max). So far, so good. I do have one question:

    My mobo shows my graphics card "memory aperture" at 64 MB, but I have a 128 MB AGP card (no onboard video). Should that setting be changed to 128?

  8. Probably wont make much of a difference. Try it and see if you can tell.
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