P8Z68 - V Pro Gen 3 cold boot problem.

[Michaeljcox24]

Ok so I fixed the SLI issue, now onto this.

About 4 of the 7 times I boot the machine up in the morning, fans come on, but no output to the monitor. Machine switches itself off, reboots, and then goes through the post screen, and then the next screen there is a white flashing cursor, followed by one below it. However, it hangs on that white flashing cursor forever.

Only way round is hard reset, (sometimes also needing power cable pulled out of back of power supply)

Things I have tried:

I updated to bios 0402

Enabled power on by PCI-EI

Disabled PLL overvolting

Enabled 'keep current' in bios post settings (which made it ten times worse and needed jumper reset to get back to normal operation.

Running out of ideas now. Anyone come accross the same problem?

 

[kilobravo]

If you use xmp profile and auto dram volts this may be the issue.Try set ram at specified settings manually.

 

[Michaeljcox24]

I set memory manually does that override xmp?

 

[kilobravo]

Disable xmp first,then manually set.

 

[Michaeljcox24]

ok will try tonight. Asus tech support mentioned xmp too (as well as running with one stick which would be a complete pain)

Once I get this fixed, rig will be fully 100% operational

 

[Michaeljcox24]

Edit...

I just downloaded the manual to have a look, i don't use XMP, memory speed and voltage were set manually when this was happening.

 

[kilobravo]

If you have set 1.5v dram voltage,maybe 1.56-1.6v is required for the Corsair vengeance rams.

 

[Michaeljcox24]

I was thinking along the same lines, but the thing is, the memory is rated at 1.5 volts. I haven't come across any literature that says if you o/c a sandy chip and install 2x4GB modules then you need to up the ram voltage to 1.55.

 

[kilobravo]

Some of the vengeance need 1.5-1.6v. in the specs.

 

[Michaeljcox24]

Increasing voltage makes no difference, and now its blue screening and locking up on the wimdows loading screen with irq not less or equal

 

[kilobravo]

What oc do you have? Up to 4.5-4.7ghz should be easy enough.Past that there some minor tweaks to stabilize oc.

 

[Michaeljcox24]

4.6 should be a breeze

 

[kilobravo]

Yeah 4.6 should be easy.Running F@H at 4.5ghz,only vcore and LLC adjusted.

 

[Michaeljcox24]

This fault is really doing my head in. Could be slots on the board or the ram itself. ive had dodgy slots on an asus board before so i know its a possibility

 

[kilobravo]

Im leaning to dodgy ram.When i try to tighten timings on vengeance rams,i have this same behavior of yours.

 

[Michaeljcox24]

Well. that will be my first port of call because its easiest thing to change. ill have to contact the shop tomorrow, explain the problem and see what they can do

 

[Michaeljcox24]

Pretty sure ive solved problem. i looked at the specs for vengeance memory and the command rate is 2t. however, its not quoted on the side of the module so you would never know. When you put the timings into the board manually the default command rate is 1t, which i never noticed until going through every bios setting with a fine comb last night. set it to 2t and not had one bad boot since.....

 

[kilobravo]

Should have thought this myself.The Vengeance rams are poor at best to tighten timings.I was certain it were ram issues.

But nice solved .

 

[yassarikhan786]

My vengeance RAM is pretty much the same. It should work fine at 9-9-9-24 at 1600MHz, but I had to change the timings to 9-10-9-27 for it to be stable at 1600MHz. Command rate is still 1t though.

 

[Michaeljcox24]

Mine is cas 8 so next job is to get overclock stable @ that timing. if its not possible ill just stay at 9 i dont think it will make the earth move