UD5 and i7

[Robert]

Basically I got it to run at 3.2 (not primed) and it seemed fine...however I just couldn't hit 3.8 (would go into a reboot cycle).

Eventually I got 3.8 with the following settings:

1.35v CPU
1.255 QPI
1.64 RAM
X36 QPI
x13 uncore
6 RAM divider
190bclk

It seemed fine - again not primed. I went to work yesterday and came home, turned it on and I got the reboot cycle again. Now it won't post with 3.8 as it just goes into a reboot cycle.

I did get 3.8 and it primed fine for 3 hours before I had to turn it off...but next day on a cold boot it just cycled and I had to reset the CMOS

[sadbuttrue]

Same motherboard (if an 1156) and an i5 here. I've found that the VTT needs to be at least 1.3v for 3.8ghz(not entirely happy with it this high, but needs must). I can drop the VTT to 1.18v and run memtest/prime/linx for hours on end, only for it to reboot itself at some random moment while idle/gaming etc.

While experimenting with a low VTT I had a random reboot, resulting in only a single memory stick being recognized. Soft booting and entering the bios still showed only a single stick. Both were recognized on the next cold boot.

On another random reboot at an even lower VTT I experienced the boot cycle you mention, although for me a cold boot was sufficient to resolve.

Could too low a VTT result in the memory connection being 'lost'? This would surely explain a reboot cycle, as the PC is powered on in a state where it would only get with available memory, but each attempt to access memory fails.