Cold boot issue with P5Q Pro after memory upgrade

[xaldub]

Hello there , first post here and I'm wondering if anyone can help.
Recently I tried to upgrade my memory from 4Gb to 8Gb - adding an extra matched set of 2 X 2 Gb Corsair Dominator PC28500C5 1066Mhz to the ones I aready had installed.

To cut a long story short, it didn't go smoothly but after reducing the DRAM frequency to 800Mhz, increasing the NB voltage to 1.4 and manually setting the memory voltage to 2.1 V I was able to eradicate random BSOD's and get the system running stable.

But ....

Ever since I've had an unusual issue - the PC won't cold boot after being switched off for a long interval eg. overnight. The fans power up, I briefly get the Asus splash screen but thereafter just a black screen and the OS doesn't load. If I press the reset switch, or power down and reboot, it POST's correctly and runs smoothly thereafter. I've tried reconfiguring my system back to just 4Gb but the problem persists. I have even upgraded the BIOS, tried booting with just one stick of RAM, different memory slots etc .....but I just can't get rid of this cold boot problem.


My PC specs :

Asus P5Q Pro
Corsair HX620 PSU
Corsair Dominator DDR2 PS28500C5 1066Mhz ( 2 x 2Gb )
BFG 8800GTS 512Mb
2 x SATA WD Caviar 640Gb 32Mb cache HDD's
Optiarc DVD RW
Samsung Syncmaster 215TW Monitor

Anyone had similar problems, or comments on how to resolve this ? My system was functioning perfectly until I tried to add more memory. For this reason I'm doubtful that is suddenly the PSU giving out on me, or some other hardware issue.


Thanks in advance

 

[xaldub]

Thanks, haven't tried the latter. Will take several hours at least until I know it works, because the cold boot issue only occurs after the PC has been shutdown for several hours at least.

 

[xaldub]

I tried taking the CMOS battery out - and then loading with default BIOS. Still caused cold boot issue. Later went through same procedure but configured voltages manually for memory and Northbridge memory controller. Still no joy.

As has been suggested, I've cleared the CMOS again ..and this time I'll enable load line calibration. Does that option minimise vdroop ? I won't know if this is successful tomorrow.

It's all strange really, because before I tried putting extra memory in the PC used to work perfectly on BIOS auto settings. Now, even they don't seem to work.

 

[xaldub]

Ok, just to update on the situation.

This morning I did a cold boot on the PC ( having been switched off overnight ) and the display came on, machine went through POST then began loading the OS. At this point, the monitor dimmed then it just went to a black screen - almost as if it had gone into sleep mode. There was no response to keyboard or mouse, but when I recycled the on/off switch on the front of the monitor it brought an image back ( Vista waiting at the logon screen ) then dimmed again before presenting another black screen. I pushed the on/off switch on the monitor once more and this time the picture came back - and stayed on.

Any comments on why it's doing the above ? Is this some weird power setting/ sleep mode I need to disable in OS or BIOS ? Or is it more symptomatic of the video card slowly dieing ? Remember this all started after I tried to simply upgrade memory from 4Gb to 8 Gb