TechSpot

FSB or Multiplier

By ChrisLam
Jul 29, 2007
Topic Status:
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  1. When overclocking, what are the advantages and disadvantages of raising the FSB rather than the multiplier and vice versa?
  2. thehacker

    thehacker TechSpot Enthusiast Posts: 176

    i have the same question to ask......
  3. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 4,265   +41

    It depends on your motherboard and cooling of course. Some motherboards will allow you to have a high fsb so increasing the multiplier isnt needed, but for those mobos that have a low fsb rating, you can increase the multiplier to get a similar overclock.

    From what I read, increasing the fsb in turn increases the vcore voltage, which will make your temps rise more than increasing a multiplier a few notches.
  4. thehacker

    thehacker TechSpot Enthusiast Posts: 176

    thanks for replying but wat if there is no option in bios to increase the multiplier? is my multiplier locked or my mobo doesnot supports it??
  5. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 4,265   +41

    more than likely your multiplier is locked, telling us that you have an intel chip :p
  6. Cinders

    Cinders TechSpot Chancellor Posts: 1,313   +12

    You have to pay through the nose to get a processor that will allow you to raise the multiplier. As far as I know only Intel's Extreme Edition and AMD's FX processors allow you to raise the multiplier. Because of Cool and Quiet technology the processor's multiplier can usually be brought down.
  7. CMH

    CMH TechSpot Chancellor Posts: 2,573   +9

    lol, so many replies, and I STILL don't see the question being answered. I'm interested in it myself.
  8. ChrisLam

    ChrisLam Newcomer, in training Topic Starter Posts: 104

    Would the processor perform better if, for example,

    FSB = 500MHz, Mulitplier 5

    or

    FSB = 100 MHz, Multiplier 25
  9. mica3speedy

    mica3speedy Newcomer, in training Posts: 205

    real world use they are the same. Some benchmarking tools will get higher scores with the higher fsb though.
  10. Starless

    Starless Newcomer, in training

    Wow, no one really answered this question yet :)

    Raising the FSB has the advantage that the speed of all FSB related components (CPU and Memory) are raised too, so your system will have a much better performance then when raising the CPU's multiplier only. (Example, a system with a FSB of 260Mhz and a CPU multiplier of 10 (2.6Ghz), will run much faster then a system with a FSB of 200Mhz and a CPU multiplier of 13 (also 2.6Ghz))

    Usually the disadvantage of raising the FSB is that it depends on a lot of other factors how far you can actually go with it and it's easier to raise the multiplier.
    A common method when starting to overclock is to first lower the multiplier and then see how far you can raise the FSB and still have a stable running system. Then continue from there by raising the multiplier again.
  11. Cinders

    Cinders TechSpot Chancellor Posts: 1,313   +12

    The FSB should be raised to overclock your computer. Raising the front side bus overclocks both your processor and memory. If your memory and processor are capable of being overclocked you should raise the FSB because your computer will be faster than if you just raised the CPU multiplier. If your memory wasn't overclockable then you'd just raise the multiplier to allow your memory to remain stable. Having an unlocked multiplier allows you to fine tune your overclock.

    I have an FX-60 running at 3.0GHz. Normally it would run at 2.6GHz at a front side bus of 200MHz. I've overclocked my memory to 250MHz and lowered the multiplier to 12 to achieve the processor overclock. My computer will not start at any CPU voltage at a multiplier of 12 and an FSB of 250 with my current cooling. If I didn't have overclockable memory I could keep the FSB at 200MHz and raise the multiplier to 15 to achieve the same CPU overclock, but I get much better memory bandwidth at 250MHz than I do at 200MHz.

    I could probably push the processor to 3.1GHz if I lowered the FSB 239 and raised the multiplier to 13, but I got tired of experimenting, and I'm happy with the overclock I have.
     
  12. Matthew

    Matthew TechSpot Staff Posts: 6,052   +84 Staff Member

    This thread has been dead since last July :confused:.
  13. Cinders

    Cinders TechSpot Chancellor Posts: 1,313   +12

    Yep yep yep, but it popped back up in my subscription list, so I figured I'd try to communicate my thoughts better this time around.
  14. Starless

    Starless Newcomer, in training

    *no comment*
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