5GHz crashes system after Windows update

[djcoder]

First off - I'm running an i7-4770k with an ASUS Z-87A motherboard and a NZXT Kraken X40 CPU cooler.

For about 6 days now I've been running at 5GHz no problem. Last night, I installed a Windows update. Once I rebooted, my system booted fine... but I do Folding@Home on my desktop when idle, so once the screen turned off, my CPU went to 5GHz full utilization... and the system bluescreened.

I've messed around with the settings, and I've even tried setting the voltage higher (I run at 1.325V, I tried 1.350V). I confirmed that it repeats by running prime95 - the BSOD/freezeup normally kicks in after about 5 minutes or so, but sometimes it does it right after login when applications load. (the system hands off to Windows at full turbo frequency). The system was working perfectly at 5GHz when I ran prime95 before - for almost a week! - and I ran prime95 for about 3 hours to test it when I first set it to 5GHz.

So far I've tried:

• Putting it to 1.350V - doesn't work
• Putting it to anything less than 5GHz - this works, I'm running at 4.9GHz at 1.325V and I'm running prime95 whilst typing this
• Increasing liquid cooler fan speed - doesn't work

I'm pretty pissed that it's suddenly stopped working, with no explanation - in the 5 minutes that I run it with prime95 it works with only 1-2degree temperature increase over 4.9GHz.

I assume the fault lies with Windows not liking the 5GHz overclock after the update for some reason, seeing as there is no other visible explanation.

Here's a photo of AI Tuner showing my current (stable) config - I just screenshotted this:

I have RealTemp still open here and throughout this entire post it has maintained those same temperatures. It went to 83 on the first core for a second, but it's not jumped anywhere near the thermal junction max.

I'd really appreciate some input on why it's doing this :/
Thanks!
-Cameron

 

[unclewebb]

With RealTemp reporting your CPU with a multiplier of 38.2 instead of the full 39; that's usually a sign of throttling. Your CPU is not at the thermal throttling temperature so it is likely hitting the turbo TDP limit. Try increasing that value in the bios.

5.0 GHz is an aggressive overclock. I think the recent Windows update and your instability issues are probably just a coincidence. It's not unusual for a new CPU to have a reduced maximum stable overclock after its initial break in. The difference in performance between 5000 MHz and 4875 MHz is only 2.5%. For such a small gain, it's not worth pumping extra voltage to it to try and get it stable. I would just run it at 4875 MHz for a while and hope that it stabilizes here without degrading further. There's no shame in running a 4770K at 4875 MHz.

 

[djcoder]

With RealTemp reporting your CPU with a multiplier of 38.2 instead of the full 39; that's usually a sign of throttling. Your CPU is not at the thermal throttling temperature so it is likely hitting the turbo TDP limit. Try increasing that value in the bios.

5.0 GHz is an aggressive overclock. I think the recent Windows update and your instability issues are probably just a coincidence. It's not unusual for a new CPU to have a reduced maximum stable overclock after its initial break in. The difference in performance between 5000 MHz and 4875 MHz is only 2.5%. For such a small gain, it's not worth pumping extra voltage to it to try and get it stable. I would just run it at 4875 MHz for a while and hope that it stabilizes here without degrading further. There's no shame in running a 4770K at 4875 MHz.

The CPU speed fluctuates a decent amount between 4875 and 4776. I know it's not a big difference but it's just being able to say the processor runs at 5GHz really.
I'll keep it at 4875 for a while but if that starts to be a problem then I'll lower it a little. I hope you can set multipliers in the second decimal place, then I'd set 38.16 just for fun.

I actually think I got a pretty good chip since I don't see many people running at this clock speed on a 4770k.

 

[unclewebb]

When fully loaded with Prime95 Small FFTs, the multiplier should remain stable at the full 39.0 in RealTemp. If it doesn't, you probably need to increase the Turbo TDP values in the bios until it is stable. A stable multi when fully loaded helps to stabilize your CPU. When RealTemp reports your multiplier at a fractional value, that means your CPU internally is rapidly switching between different multipliers.

I think your CPU is way above average. The full 5 GHz would be nice but most enthusiasts would camp outside your house waiting for you to kick that 4770K to the curb.