Are you looking for a synched overclock or just trying to max out each component?
Heres a simple guide for just overclocking the memory if you don't care about synched overclocking-
First step is to find the stable timings at the stock speed of your memory (or motherboard if you have faster than PC6400). Two examples here, first is if you have some PC5300, the motherboard will default the memory speed to 333MHz, even though it supports higher. The other option is with something faster, like PC9600, at the moment, the highest supported memory speed is PC6400, so the motherboard will default that PC9600 to 400MHz. Then at that speed, lower the timings one at a time until the lowest values that are still stable have been obtained.
After the tightest timings at stock are found, raise the timings one at a time until you find the one that makes the largest MHz increase over your previous timings, and find the max. Repeat until higher timings do not gain more than 10MHz.
For a more explicit breakdown, I'll explain what to do more explicitly with some examples.
Get memtest86+ and install it on a floppy or cd if you don't have a motherboard that has it on the bios (DFI). Boot with the memtest floppy/cd in to make sure it boots into that instead of your normal OS. Once you have confirmed this, hit escape to reboot and then go into the bios.
What we're gonna do the first step I talked about before, finding the tightest timings the memory can run at stock speeds. First, manually set the timings to the rated speed of the memory, no "auto" settings should be seen for Tcl, Trcd, Trp or Tras!
From here, we will work on one timing at a time.
start with Cas latency (Tcl)
1. Lower timing one step, save bios and restart, boot into memtest.
2. In memtest, change to test #5, loop it one to three times. (less if you're in a hurry, more for more 'accurate' results)
3. If memtest displays no errors, go back to step 1, if you do get errors, continue to step 4. If it does not boot, either hit the reset button while holding down insert or clear the BIOS, re-enter the settings that you had just tried to boot with and continue to step 4.
4. Raise timing one step, then go back to step 1, but with Trcd, then Trp. Adjust Tras when needed to keep it equal to Tcl + Trcd + 2
When completed all 3 timings, run a few full passes of memtest to ensure that it is at least slightly stable. Then write down what the timings are somewhere. We have just completed the first step!
Now, the where the real fun begins. We're gonna find the maximum speed at each set of timings, however, it's gonna take a long time unless you're good at guessing
1. Bump up the FSB or HTT up 2-3 MHz
2. Boot into windows
3. Run SuperPI 2M
4. If no error, continue to step 5. If there is an error, go to step 6.
5. Raise FSB or HTT 2-3MHz with a program like clockgen or systool and go back to step 3.
6. Drop the FSB or HTT 1MHz
7. Run as many SuperPI 32M instances as your CPU supports threads (ie: dual core, run two instances of superPI out of seperate folders). If there is an error, go back to step 6. If no error, continue to step 8.
8. Run 32M one more to double check stability, then write down the MHz obtained along with the timings and voltage used to get there. I recommend making a chart for this, tabulating the maximum MHz at each set of timings and voltage.
Now we have two options: bump up memory voltage, or raise the timings. I advise first finding the timing sets that should be focused on, then change the voltage with each of these until you have tested each timing set with the voltage settings that you feel are safe for normal operation. Either way you go, follow the above steps to find the maximum stable speed. You should always test things systematically.
For the timings, you should change one timing at a time until you find which ones make a significant effect on maximum MHz. This is something that will take a bit of playing around and guess-work until you find something that works out well. Again, be sure to only change on timing at once, and do not touch the voltage at this time.
If you decide to increase voltage, be sure to only change voltage, leave all the timings alone. One rule I try to follow at all times when overclocking is only change one variable at a time. If more than one is changed at once, you don't know how much each is effecting effecting stability.
Start out at stock voltage (2.6v for DDR1 and 1.8v for DDR2) and test 0.05v to 0.1v higher, find max, increase voltage again, find max, etc.. until you decide that the voltage is high enough.
This will vary for all ICs, refer to the quick guide for ICs at the end of this guide. Be very careful with voltage, as some can fail prematurely if you give it too much. Also, always be aware of the temps your sticks are running at when overclocking.
Edited by crystalklear64, 10 July 2008 - 05:14 PM.