Athlon II X4 640 and DDR2 800

Can an Athlon II X4 640 run with DDR2 800, or does it require faster memory? My motherboard is the Asus M4A785-M with the AMD785g chipset.

I'm having trouble getting XP to recognize all four cores, and I'm wondering if the CPU/memory combination is the problem.
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  1. If the board supports the CPU it should not be a problem. Do you have the required BIOS for that CPU?
  2. rolli59 said:
    If the board supports the CPU it should not be a problem. Do you have the required BIOS for that CPU?

    Thanks. I flashed to the latest BIOS (version 1006) without any luck. Maybe I should downgrade to the BIOS version they mention for the CPU, although you would think it would be supported in the latest version if it is supported at all.
  3. Latest BIOS includes all fixes from older so no need to go back. Did you install XP with that CPU?
  4. RAM type, size, or speed won't affect how many cores are seen.....

    How do you know XP doesn't recognize all the cores? JUST hit CTRL-ALT-DEL; then start up the task manager and hit the Performance tab. There will be a separate graph for each CPU core under CPU Usage History....

    OR, download & install CPU-Z and it will tell you how many "cores" on the CPU tab.....
  5. Athlon II X4 has memory controller for DDR2 and DDR3. It will come down to motherboard support.
  6. Thanks for all the answers and suggestions. My overall problem is that when I install XP Pro SP3 with APIC enabled in BIOS, I always get a BSOD (No_More_IRP_Stack_Locations) after the first reboot. If I turn off APIC then XP will finish installation. However, no APIC means no multi-core and I get the Standard PC HAL (I've tried forcing the APCI Multiprocessor and even the MPS Multiprocessor HALS, but no luck). There is only one core present in Task Manager.

    I don't think this is due to any faulty hardware. I can run Ubuntu from a LiveCD with no problems and with all 4 cores running. I've also done an overnight Memtest with no errors. There just seems to be a communication issue between XP and the BIOS. I've tried tweaking all kinds of BIOS settings (and I must have been through at least a dozen XP install attempts), but the only thing that gives me a successful install is with APIC disabled.

    Dadiggle, I'll try the 1.8V settings on my RAM. I've saved tweaking the voltages for the last resort. I know it is pretty safe, but I'm always afraid I'm going to fry a component.
  7. I've got an old Sempron (I actually had it in this board briefly, so I know it works). Maybe I can do an end-run around the XP install. I'll install XP with the Sempron and get all my drivers installed. Then, I'll swap the Sempron with the Athlon II X4. If I cross my fingers, maybe XP will recognize the hardware change and give me the APCI Multiprocessor HAL.

    Any thoughts on this approach?
  8. Yes, Just Check My Machine Specs, Im Running A Phenom II On An AM3 With 6GB DDR-2 CAS4
  9. Quote:
    you mean AM2+ and not AM3.

    to let you know i had an m4a785-m asus board and it was AM3 with ddr2 any AM3 board should also hold an AM2+ processor weather ddr2 or ddr3
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