22-08-2008 until 31-12-2009
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Overclocking Methodology
by eva2000
Updated: August 22, 2008
There's no one set of settings that will work for everyone. There's only a basic methodology to overclocking and it doesn't change regardless of platform you're on whether it be s939/AM2 or Intel 965P/975x/P35/X38/48/P45 or Nvidia 650i/680i/780i/790i.
- Find your stable stock cpu/memory speed configuration settings. Yes that means to memtest86+ v2.01 and windows stability test (prime95/orthos/super pi/3dmark) you cpu and memory at stock speeds to confirm they're stable.
- Find the max stable memory overclocking frequency and timings/subtimings of your memory. To do this try to keep cpu FSB at stock speeds or as close to stock speed/FSB and use memory dividers where possible to find your upper limits of your memory frequency. Regardless, of platform memory clocks and timings/subtimings respond to mainly 2 types of voltages, vdimm memory voltage and NB - northbridge voltage. On some platforms such as Asus Commando/P5B Deluxe/P5K series and Striker Extreme they also may respond to vFSB and SB - southbridge voltages.
- Next part is really a follow on from step 2, that is to find out your memory's max overclocking frequency and timings/subtimings with each memory divider to see if there are differences in internal latencies with each memory divider. Example, is on Asus P5B Deluxe 4:5 divider has a very very tight internal latencies compared to 1:2, 2:3, 3:5 on the Asus P5B Deluxe. This means while you could clock you memory to 600mhz on 2:3 divider with say 2.4-2.6v vdimm, you might need 2.4v just to get to 500-520mhz on 4:5 divider and that 500-520mhz on 4:5 divider might only be a fraction slower in performance than 600mhz on 2:3 divider. Each motherboard is different, so you need to test this for yourself. Again, the key is in 2 types of voltages, vdimm memory voltage and NB - northbridge voltage and basically how good your memory is.
- Next, is to find your max FSB frequency. That means dropping your cpu multiplier if you can and trying your max FSB at 1:1. From step 2, you would of already found your memory's max overclock frequency so bear this in mind when you are testing for max FSB at 1:1. Max FSB on core2 duo platforms respond to several different voltages depending on the motherboard and it's chipset they'd include vFSB, CPU PLL voltage, GTL+ Reference voltages and the most important of them for Intel 965P/975x/P35 or Nvidia 650i/680i at least is NB - northbridge voltage. Better Northbridge and Southbridge cooling (for Asus P5K series seeing as CPU PLL volts is tied with SB voltage on this series), may result in slightly better max FSB.
- Regarding voltages and settings in bios in general, I usually start with AUTO values to initial tests, then retest stability and performance to compare with manually set values. Then for voltages I pick the lowest value I can select for manually setting the default voltages which I'd use for my base reference overclocks. I rarely will use AUTO voltages for the important voltages such as Vcore, Vdimm, NB and vFSB. Update: For P45 chipsets be careful of AUTO and even lowest selectable voltages for vFSB/CPU VTT, NB, CPU PLL etc and some P45 boards reported to auto jack up voltages as FSB rises and you could be using cpu killing voltages that you are unaware of!!
When you have tested for all 4 steps outlined above, you can then put it all together to find your optimal overclocks and test for overal system stability. This would require alot of reboots and testing with both
memtest86+ v1.70 initially followed by windows stability tests - basically the same or similar procedure and applications I outlined for AMD64 Overlocking Guide
AMD64 Overclocking Guide (07/11/06).
The above outlined steps you can see in action in nearly all my motherboard/cpu overclocking threads hence why I never really did an Core 2 Duo overclocking guide as basically every core2 duo cpu/board overclocking thread I started is a guide as such - all you need is to read the threads carefully
Some examples of the steps outlined include:
Note, not all threads follow the outlined steps fully since some of the steps are already done before hand i.e. you already know your cpus max FSB or max cpu mhz and/or memory's max overclocking frequency and timings/subtimings from prior tests with the same memory on the same motherboard. Hence, why I think memory overclocking is the most important part of the whole system overclocking process. Without good overclocking memory the rest of your system will suffer in terms of optimal overclocking potential.
If you have questions specific to your cpu/board/memory please
DO NOT private message me but rather start a new thread in the relevant forum on i4memory.com outlining your system specs, bios settings, bios version etc.
