The theory behind the memory voltage mod (and others are free to correct me if I'm wrong) is that sometimes when you max out on overclocking, it's because of the memory rather than the CPU. So, the thought is, you might be able to take things higher if you boost the voltage to the memory in the same way you do to the CPU when you're overclocking. I say "might" because when I was originally researching this months back, I don't recall anyone saying it actually helped them go higher. There may be plenty of people out there that it did help and, if so, hopefully they'll chime in. I do remember some people saying, however, that they thought it was bunk. It may come down to trying it for yourself to see if it helps. From other stuff I read, it seems that if memory is holding your overclocking back, more often it's because they get too hot rather than from a lack of voltage. Perhaps a fan (or fans) blowing on the memory would be more helpful.
While I'm still in the long, drawn out process of putting my system together (going on 7 mos. now - 3 kids and work, thank you very much) I haven't gotten to the stage of actually doing the mod, but I have the pre-wired potentiometer to do it. You can make one yourself or check with Larry Quinn, a member of these forums, at [email protected] (if that email address is still good) to see if he still makes them for purchase. I believe many people, including Larry, were using a 100K pot.
(What follows is an edited version of a post of mine from the archives on how to do the Mem Volt Mod, which also paraphrases previous posts from Doctor and Ralphing. Just trying to give credit where credit is due.)
VR = Variable Resistor=Potentiometer=Pot. They all mean the same thing. They usually have three terminals. You connect either one of the side terminals on the pot to the number 3 pin of the HIP6521 chip on your motherboard by either soldering the wire to the pin or using a Pomona Grabber. (See attached image below to find the number 3 pin.) And you attach the wire from the center terminal of the pot (the ground) to one of the screws that secures your motherboard to your case/motherboard tray.
You're done. You adjust the pot until you get to voltage level you want. Make sure you start out with max resistance and work your way down to the desired voltage so you don't fry your memory, HIP6521 chip or motherboard.
If you're not comfortable soldering something that small and don't know where to get a Pomona Grabber, once again, check with Larry Quinn. He sells pre-assembled pots with a Pomona Grabber on one wire and a screw terminal on the other wire for attaching to the ground screw. He automatically sets them at max resistance so you don't fry your chip. You just turn the adjustment until the resistance is lowered enough to change your voltage to what you want. He originally sold them for $10 US each. I bought two so that I could do both the vmem and the vcore mods.
As a disclaimer, I'm in no way personally suggesting you do this mod. If you do it, you do so at your own risk. If it is done incorrectly, you can fry your memory or HIP6521 chip, damaging your motherboard. Use judgement and caution here.
I will give this a try for sure. Hopefully this does help me a little. It seems my memory voltage is actually low according to the BIOS. The same was the case with my Core voltage. I actually have my Vcore set to 1.65v in the BIOS just to actually get 1.5-1.54 or so.