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Peanya wrote: Iâ€™m writing this with a goal of 250MHz on the memory (DDR500). If you want to go farther, itâ€™s up to you.
The first thing to do is lower the memory ratio and CPU ratio. A multiplier of 8 on the CPU will do, and set the memory to the 333MHz speed. Some boards will have a ratio of 6:5 instead. Next, weâ€™ll raise the LT bus multiplier to 4 instead of 5, and set the base frequency to 250MHz, while leaving everything else at stock voltages. Now check for stability. A good test would be to use multiple apps that take advantage of the video bus and your disk drives. I tested using EQ while defragging. SANDRA also has tests which can help here. If you want to be able to push your memory further (not yet, but after weâ€™ve tested the LT bus) then you can reduce the LT multiplier to 3, lower the memory ratio another notch, and set the CPU multiplier lower again. Now you can check the frequency all the way to 333MHz. What weâ€™re doing here is testing to make sure thereâ€™s no weakness in the LT bus, and if it will overclock well. Going past 300MHz wonâ€™t benefit, as no current memory will overclock that far. If youâ€™ve lost stability with either the 4 or 3 multiplier, try reducing the speed a little or give a very small bump up to the LT and Northbridge voltage.
Peanya wrote:Once weâ€™ve determined the max LT frequency, if any, now we can move to the memory. Set the LT freq back to stock, and leave the multiplier to 4. Weâ€™re still not overclocking the CPU just yet; so leave that multiplier at 8. From here, set the memory back to DDR400 or 1:1. Assuming the LT was stable to 250MHz, weâ€™re now going to overclock the memory. Overclock it just like you would any system: raising the voltage and/or relaxing the timings as necessary. Of course, always check the stability of the system.
Peanya wrote:So far so good? Great! Letâ€™s get to the final part, the CPU. Now we can set the multiplier back to normal, now that we know the limits of the memory and LT bus. Letâ€™s assume that both are stable at 250MHz. We can simply reset the CPU multiplier back to stock and slowly raise the LT speed until we lose stability. Then we will know itâ€™s time to raise the voltage. It seems that the AMD64 can be over volted easier than many other CPUâ€™s. Then again, this might be to me using a 90nm CPU vs. a 130nm.
This will probably leave a few questions open to the beginner overclocker, but this is a very brief guide for the experienced. Basically the biggest question will probably be the LT bus. This is the bus that connects to the AGP,PCI, IDE, and almost everything else in the system. Only the memory is on a separate bus. Overclocking it past 1GHz can result in a loss of stability, so thatâ€™s why we have the multipliers.
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