Hi all. Got a strange one here for you, especially any Corsair employees.

I've spend a fair amount of time recently trying to establish why my machine won't resume from Sleep in Vista when I press the power button when it's over clocked. It just gives a black screen, no video at all. Sleep is great and I want to use it as it allows you to be back up and running very quickly, especially given the hideous shut down time I'm currently experiencing with Vista.

I did a lot of trouble-shooting with BIOS settings and have narrowed the problem down to the memory clock speed. My motherboard is a Gigabyte P35C-DS3R, CPU = C2D 2140 @ 3.2 GHz, memory = 2x1Gb Corsair XMS2 PC6400, PSU Akasa PaxPower 460W.

I have established that when the timings are set to 4-4-4-12 and the memory is synchronous with FSB (i.e. the stock 800 MHz) the machine goes in and out of sleep will-nilly with no issues. The machine is also stable in games etc I should add. However if I nudge the divider so that the memory clocks at 960MHz (stock volts) with standard timings, although the PC boots and operates perfectly normally, it refuses to awake from sleep mode, presenting me with a black screen though HDD activity continues as normal. This requires a power down and cold boot, at which point the over clocked BIOS settings have returned to default.

I'm not necessarily blaming Corsair memory; the way I see it there are several possibilities as to the cause of the problem:

- insufficient power on 5V rail (but then why would it work fine @ 3.2GHz stock memory settings)
- memory not capable of functioning normally @ 960 MHz 4-4-4-12 (still works fine in memtest games etc)
- bug in Vista
- bug in the BIOS
- chipset drivers

All my BIOS and chipset / video drivers are the latest versions; I updated them in an attempt to solve the problem. What do people think is the problem, and has anyone experienced this before? What voltage is this memory theoretically safe up to? I would have though that £100 of Corsair memory should be able to function @ 960 MHz at standard timings.

Really appreciate any thoughts on this subject, as although my machine is operating very quickly and I'm more than satisfied with it, I'd be curious to learn the reason behind it.