Overclocking i5 2500k momentary throttling?

Since I've had my current system just over 2 years now and games are starting to struggle a bit on it, I thought before I go dump a load of cash on a new system I'd give overclocking a go, see if I could iron out some of those framerates. I have a Gigabyte GA-Z68AP-D3 rev 2.0, which I know isn't an oc'ing board, but it should be capable of at least a modest oc right?

At the moment I have just been upping the multiplier and I have got the system up to 4.4ghz without touching any of the other options in the bios. In CPU-Z the vcore is running at 1.332 and while the system is making it through the night in Prime95, I noticed after roughly 30 mins of stressing the CPU it throttles back down to 1.6ghz momentarily and then pings back to full speed - this happens maybe every 30-40 seconds. I have a Corsair H75 cooling the CPU but I checked the temps and it's peaking at around 65C which isn't that bad, certainly not enough to be thermally throttling.

Is this throttling a problem and if it is how would I solve it?

Cheers guys

 

Sounds like speedstep to me (look for EIST). Disable it in the BIOS

 

Thanks for the reply Pookie.

I have Speedstep disable in the bios, still doing it.

 

I had the same issue on my old Gigabyte board when trying to overclock my FX-8320. It would do the same as your i5. A core would drop to 1.something GHz briefly then jump back up to whatever I was trying to overclock it to and repeat until I stopped the benchmark/stress test e.t.c. I never got to the bottom of it before I replaced the board with the ASRock in my sig which has no issues with overclocking the same CPU.

 

What are your full load temperatures on your CPU and motherboard?

 

I haven't ever seen any of my Gigabyte Z68 boards do this, but it does indeed sound like throttling.

Have a gander in bios and see if disabling any thermal monitoring helps.

id also look into seeing if another bios solves the issue.

 

Qazax - the CPU tops out at 65C, indivual cores are 65, 65, 62, 61. The sensor readings for the mobo are TMPIN0 29 , TMPIN1 25 and TMPIN2 55.

mrbungle - I have disabled most of the the CPU functions, doesnt seem to have made a difference.

 

I wonder if it might be a bad cap on the board, perhaps?

 

Wasn't there something about auto vcore overclocking and LLC causing something like this?
Does your bios have a Load Line Calibration option?

Try setting a vcore, 1.33v seems a tad high for 4.4GHz, and set the LLC manually. A middle setting should be plenty for 4.4GHz.

This would be high up on my list of things to check.

 

Oh - that's a good point - it might be voltage droop! LLC is your friend here

 

mrbungle - I have managed to downgrade my BIOS from the really naff EFI release they did recently which had next to no oc'ing controls - old school seems at least a bit better.

Spreadie/ jinq-sea - Think you are on the money guys. Entered 1.27 vcore into the bios LLC level 4 and so far no throttling! CPU-Z and HWMonitor reporting 1.248-1.26 but pretty steady. Seems the board suffers from pretty nasty vdroop, not surprising really, it's not an overclocking board. Temps down 5 degrees. Fingers crossed it'll stress for the long haul.

Cheers for the replies so far guys!

 

That era of GIGABYTE boards were horrid with voltages, not just the lower end ones.

 

That is likely more related to 8 core AMDs needing 8+2 power phase to stay stable than anything else

 

The old board was a GA-990FXA-UD3 which had 8+2 phases by the looks of it and so does my current 990FX Extreme4 too. The Gigabyte was was the earliest revision however and missed out on the better, less buggy BIOS and improved VRM cooling of the later revisions so I'm blaming that (among other things).

I'm glad OP seems to have sorted his problem out though

 

I've figured it out. Thought I'd post back to let you know I'd figured it out.

See that TMPIN2 temperature of 55c I posted earlier? Figured out that's the VRMs and I noticed while staring at the figures in HWMonitor in a trance, that as soon as the temp hit 55c the cpu throttled. So I've chucked in a 140mm fan blowing directly over the circuit and the temps are around 47-48 under full load for 12 hours and there's no more throttling!