GA-P55A-UD6 Boot Issues with a stable OC

[glen8]

Hi All,

My spec is as follows:

Intel i7 870
GA-P55A-UD6 (F11 BIOS)
Corsair XMS3 2000Mhz
Corsair Hydro H70 (with MX3)
RadeonHD 5450 (Low powered as I'm not a gamer)
Antec 550w PSU

I am using the following OC settings to get 4.0Ghz

Multi: 20
Bclk: 200
Vcore: 1.3250v
Qpi/Vtt: 1.360v
Turbo: OFF
CPU C-States: OFF
HT: ON (required for video encoding)

LLC: Level 2
RAM settings are all managed by XMP which with this OC puts the RAM to its native 2000Mhz.  I am assuming the RAM Volts are managed via XMP to 1.65v but I have manually set the RAM to 1.660v although I don't know if this setting is being used.

The machine is running fine in Windows.  Intel IBT has stressed the system and passed.  CoreTemp reports CPU at 30 Idle and 65 under Load.  Video encoding works fine running all 8 threads at 100% no problem.  I therefore think the OC to be pretty stable.

Now here comes the weird part.  Once I power the system off, it takes me about 5-6 attempts before it will power back on again.  Do you think this is a BIOS problem or that because the LLC is at Level 2 the system is undervolting the chip which is why it refuses to boot?

Thanks,
Glen.
p.s. Any OC recommendations from the Gigabyte team would be appreciated

[Dark Mantis]

Well to be honest I am not much of an overclocker myself but do the occasional dabble. My instant reaction to your post was that you were cutting it a bit fine with the power supply. As you say the memory voltage should be managed by the XMP setting. Apart from that I am afraid I can't help you much as I mentioned I would be inclined to use a heftier PSU.

[glen8]

I'm surprised at that as I thought my PSU would be more than enough.  Don't forget I'm only running a 5450 graphics card.

It's the NeoPower model not the cheap basic one

http://www.overclockers.co.uk/showproduct.php?prodid=CA-118-AN&groupid=701&catid=123&subcat=1088

[Dark Mantis]

You are probably fine with it and as you say it is the better model. The main problem I have with it (apart form the total power output) is that it uses four 12v rails and this can often cause problems as if you get a sudden heavy load on one of the rails there is nothing to take the strain. The other thing to take into consideration is that as the PSU ages the output drops considerably because of capacitor droop etc. So even after one year or so you can be down to only 80-85% total output. That is why I prefer to err on the side of caution and use  something hefty.

[glen8]

If it was my PSU at fault, wouldn't it crash on heavy load?  It's fine running all cores at 100% but it's when I come to power on I'm having the problems.  Very strange.

Maybe at Christmas I'll treat myself to a better PSU 

[Peteruk]

try the OC by dropping the ram speed to 1333MHz so that when you OC the RAM will clock up when you up the CPU bus clock.

[jojodancer]

try this sister board. many experts there:

http://forums.tweaktown.com/gigabyte/