Question about MCH voltage

[The Gonif]

Hi, I have an IP35-e with an E4500 that has been running great for a couple years. Yesterday I upgraded to the BIOS 18 listed in this forum in preparation of adding more memory and upgrading to Windows 7.

So I did something stupid, I meant to take photos of all the BIOS screens but got sidetracked and forgot, so now I've lost all my settings. I think I've got most of them back except for the overclocking ones.

Anyway, at one point yesterday I booted into Windows and then a BIOS alarm started warbling. It wasn't the CPU heat, that seemed fine. I noticed that the "MCH 1.25" setting, which was set to "Default", was reported as running at 1.56v. The Northbridge's heatsync was burning hot. I didn't know what to set MCH to, so based on the name I changed it to 1.25v and now things seem fine.

Can anyone explain why taking the automatic "Default" setting for "MCH 1.25" would result in it running at 1.56v? And further, why is 1.25 the lowest value allowed by the BIOS? And finally, did I do the right thing at setting it to 1.25? I'm guessing that when I add 2 more sticks of RAM I'll have to bump MCH up a little, right?

Thanks!

[peterb]

I cant answer the specifics - or say why the MCH voltage was set so high. It may not be the default, but just have set itself there in the bios settings (the "CMOS" during the reflash. However setting it to the lowest voltage is the safe option and, as you have found, has solved the immediate problem.

Whether r not you will need to increase it with more memory is something that you will have to experiment with, but keep the increase to a minimum required to achieve stability, remembering that overclocking and increasing voltages is adding to the stress on components, and may result in a shorter service life.

[The Gonif]

Thank you. Last night I added two more sticks of RAM so that there are four total, and ran Memtest all night with no errors. This morning I ran Prime95 for 20 minutes or so and it didn't find any errors, so maybe I won't have to raise MCH after all.