2500k - failed overclock

[Spurs]

Hello all – I recently tried to increase the overclock on my 2500k and unfortunately got something quite wrong. Here’s what I have:

2500k – was at 4.1ghz at 1.26V Vcore on air
Gigabyte GA-Z68AP-D3 rev 2.0 with UA9 (UEFI) BIOS
Corsair HX750 power supply, never had any problems with it
Single 7870, never had any problems with it
8 GB Corsair 1600 RAM, never had any problems with it

I don't remember which exact CPU HSF I have but it's not stock and temps after a couple hours of Prime95 were generally in the mid 50s. I was hoping to hit at least 4.4ghz and so the first thing I did was leave everything the same and increase the multiplier to 44x. Crashed immediately upon loading Windows.

I then made the following changes after poking around online at various OCing guides:
1. Increased Vcore to 1.3V
2. Increased QPI/VTT to 1.1V
3. Increased System Agent Voltage to to 1.125V
4. Disabled C1E, C3/C6, CPU Thermal Monitor, CPU EIST function
5. Set SATA control mode to AHCI (it was at IDE)
6. Disabled onboard GPU (it was enabled - this probably wasn't necessary but I didn't think it'd do any harm).

I then saved and exited and I now can't even get back in to BIOS. Did I get one of the above settings very, very wrong? The first time it booted the screen went black after the Gigabyte logo flashed. After that I restarted and hit DEL to go in to BIOS to reduce the multiplier, but the screen still just goes black before I can even get to BIOS. Tried at least another 20 times and it's always the same result.

Thanks in advance for any ideas.

 

[SolidBladez]

6. Disabled onboard GPU (it was enabled - this probably wasn't necessary but I didn't think it'd do any harm).

When you disabled the onboard GPU, did you have the display boot order set to PCIe? Maybe try clearing the CMOS and reloading the optimized defaults. Then start changing everything, one by one, until you can safely boot into Windows.

 

[Spurs]

I didn't change that when I disabled onboard GPU - if I had looked at it I would have set first to PCIe.

I'll try clearing the CMOS tonight... should have known to try that but never done it before. Thanks

 

[J Macker]

I didn't change that when I disabled onboard GPU - if I had looked at it I would have set first to PCIe.

I'll try clearing the CMOS tonight... should have known to try that but never done it before. Thanks

when you reset your cmos, unplug both the main atx power connector & cpu power from the motherboard as a precaution. One motherboard actually died on me because I didn't unplug them.

 

[zero2dash]

when you reset your cmos, unplug both the main atx power connector & cpu power from the motherboard as a precaution. One motherboard actually died on me because I didn't unplug them.

Never had this happen...and I assumed the board had to be plugged in to actually reset the CMOS to begin with.

 

[Spurs]

Thanks for the warnings. Is that necessary even when the main power cable isn't plugged in to the wall?

 

[zero2dash]

Thanks for the warnings. Is that necessary even when the main power cable isn't plugged in to the wall?

I've reset CMOS with the PSU hooked up to the motherboard completely AND plugged into the wall. Standard boards, 2P server boards as well...

Going on....15+ years of PC building I've never fried a board while resetting the CMOS with the board having been plugged in. I don't do it when the system is running obviously, but that's the extent of 'no-no's' that I know of when resetting the CMOS.
Sometimes if the reset doesn't 'take', the only other thing you might have to do is remove the battery.

 

[Spurs]

My motherboard manual says "Always turn off your computer and unplug the power cord from the power outlet before clearing the CMOS values." I'm going to try to reset with the main power unplugged and if that doesn't take go straight to removing the battery. If it comes to that, how long does it need to be out? Just 30 seconds or so?

 

[zero2dash]

My motherboard manual says "Always turn off your computer and unplug the power cord from the power outlet before clearing the CMOS values." I'm going to try to reset with the main power unplugged and if that doesn't take go straight to removing the battery. If it comes to that, how long does it need to be out? Just 30 seconds or so?

Yeah, 30 seconds is sufficient.

Come to think of it, I think I have reset the CMOS after flipping the PSU switch 'off'.
I've never unhooked the ATX or EPS cords from the motherboard, however.

 

[J Macker]

I've reset CMOS with the PSU hooked up to the motherboard completely AND plugged into the wall. Standard boards, 2P server boards as well...

Going on....15+ years of PC building I've never fried a board while resetting the CMOS with the board having been plugged in. I don't do it when the system is running obviously, but that's the extent of 'no-no's' that I know of when resetting the CMOS.
Sometimes if the reset doesn't 'take', the only other thing you might have to do is remove the battery.

I only had it happen with one board over the past 14 years, and hadn't had the problem with others, but I just unplug it now as a precaution. It's not hard, so I just do it.

As for the jumper, I usually only short it for a few seconds. I've never had to short it for more than that.

 

[Quartz-1]

My motherboard manual says...

Ye gods! Someone who reads the manual!

 

[Spurs]

Reset the BIOS and booted right up, no problem. Thanks guys... should have known to do that on my own but appreciate your help!