athlon 64 and overclocking

By Dantrag · 9 replies
Nov 3, 2003
  1. i read that the athlon 64 doesnt have a fsb anymore...
    so if you wanted to overclock it you can only use the multi right?
    just wondering how your ment to do it :)
  2. Justin

    Justin TS Rookie Posts: 942


    It has a front side bus, which runs at the same clock speed as the processor itself.

    Remember, the multiplier is a figure that gives cpu clock speed based off the front side bus to begin with... not having a FSB but still using a multiplier is a non sequiter. Anyways... A64/FX have the front side bus speed running at 1/1. A 1600mhz A64 will have a 1600mhz FSB.
  3. somekid007

    somekid007 TS Rookie Posts: 271

    i believe that the fsb for the a64 is 800mhz dual pumped for effective 1600 mhz. consequently a 1.6 ghz proc should have a 2x multiplier. but the a64s i have seen are 2.00ghz. so the multiplier should be 2.5. teh last time i saw multipliers this low was on pentium 166s
  4. Dantrag

    Dantrag TS Enthusiast Topic Starter Posts: 135

    but i've read that the the normal fsb is replaced by a direct link between the ram,gpu and cpu...

    can someone explain all this plzz :)
    i'm getting confused :D
  5. Didou

    Didou Bowtie extraordinair! Posts: 4,274

  6. Dantrag

    Dantrag TS Enthusiast Topic Starter Posts: 135

    lol :) better get reading :D
  7. Steg

    Steg TS Rookie Posts: 269

    as i understand it
    the 'FSB' which connects the CPU and Northbridge (both on the chip die) is 200Mhz quad pumped (like the P4 'c' s) - having read some reviews of the FX-51 some users managed to get 100Mhz overclocks - which are just increases in the FSB i assume

  8. somekid007

    somekid007 TS Rookie Posts: 271

    the agp bus and pci bus runs at a certain fraction (2/3 and 1/3 i believe) of the speed of the fsb. the processor runs at the speed figured by multipliying the multiplier by the fsb (eg. 2.4c has 200mhz fsb*12x multiplier is 2.4ghz). by upping the fsb, u up the pci, proc and agp speeds. however, agp and pci buses may not be able to take the extra speed and will lead to stability problems. nfoce2 motherboards for athlon xp allows you to lock the agp and pci bus, i dont know about athlon64 boards tho
  9. Steg

    Steg TS Rookie Posts: 269

    apartently the FSB in A64s is now the 'HyperTransport Bus' but it is basicly the same thing

  10. Didou

    Didou Bowtie extraordinair! Posts: 4,274

    This is how the HyperTransport link that connects the CPU to the rest of the system works.

    The CPU itself uses a "Universal Clock", which is a sort of FSB. It is that clock that used to OC the chip most often. By OCing that Universal Clock, you play with the CPU speed & the memory controller's speed but it does not affect the HyperTransport link. It would seem that Athlon64-FX are not multiplier locked as of yet. But there aren't many BIOSes available allowing to change it.
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