CPU speed vs memory speed


I have 4 256mB dimms of ddr266 that I want to use in a new development machine that I am building. I plan on using the Intel 865 chipset in a stock Intel board for compatibility reasons.

All the Intel D865PERL type boards say they can use 533 or 800 FSB CPUs. Are there any problems using 800FSB CPU with DDR266 memory? Can anyone elighten me as to what the performance would look like for DDR266 with these FSB speeds?

I am simply trying to pick the lowest cost cpu for my situation.

thanks ... tb
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  1. I dont think there is a problem, but my guess is that either you will need to underclock the cpu FSB to 133 instead of 200. Now since Intel CPU have multiplier lock, your cpu will also be underclocked. Lets say you have a 2.4c its 200mhz X12 =2.4ghz now 133X12= 1.6ghz or so...
    Now the other option would be to overclock the ram at 200mhz but I doubt you can reach these speed with almost any sticks...
    Anyway its a good idea to go with P4c + 865 but youll get a huge performance hit using DDR266, this could be a temporary solution until you buy DDR400 as I strongly suggest yo do so with that kind of system.
  2. As always money is the issue sending me on this hunt.

    From what you are saying it would be best to just buy the P-4 CPU with 533 FSB for the best match???

    I have a similar development machine, 2.26 533FSB CPU with DDR266 memory and performance is fine. I only want to get the max out of the new box given the parts I have on hand.

  3. Pick up a nice 3.06 :) It's 533fsb has HT and is pretty tight.

  4. Don't Intel boards support asynchronous CPU:RAM operation?
    I know the Abit/Asus/etc P4 boards using the same chipset do. He should be able to set the RAM to 2:3 of the CPU FSB to run everything at stock speeds with a 200(800QDR)FSB CPU.

    <font color=red>The preceding text is assembled from information stored in an unreliable organic storage medium. As such it may be innacurate, incomplete, or completely wrong</font color=red> :wink:
  5. Hehe trudat how come I forgot that?
    You can set the ram to run asynchronous you will stil get a performance hit butyou still get the benefit of a P4c and even use some of the dual channel.
    Still if you can shell out a few bucks for DDR400 later on youd see a good perfomance increase...
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