Overclocking 2500K, trying to understand weird behaviour

CalsonicGTR · Nov 20, 2011

I've been doing some overclocking today, and I've been noticing some weird behavior. While I'm stressing with Prime95, my multilplier will occasionally fluctuate (between 38 and 42). Is there a setting I need to disable to make this stop? Also, when I end the test CPU-Z shows that the multiplier drops to 16x, while every other program continues to show 42. Is this just a CPU-Z quirk?

4GHZ_or_bust · Nov 20, 2011

Sounds like turbo boost is kicking in, then throttling back due to heat. I'd start with temp monitoring first to make sure you're not getting too hot.

GoD_tattoo · Nov 20, 2011

Your power saving features are enabled. Don't know what they are on that board, but they used to be the C1E stuff.

CalsonicGTR · Nov 20, 2011

Ok I disabled all of the C States (C1E, C3, C6) and Speedstep and tried again. Multiplier still fluctuates. Temps hit a max of 61/66/63/61 for all 4 cores with a 1.28 VCore. Im, using a Hyper 212+, are these temps high enough to activate the thermal throttling?

Dougshell · Nov 20, 2011

bud had the same issue, tried a million settings and it ended up being a well known bios issue. Update fixed it (actually a roll back) this was on a MSI GD80 (B3)

Check your motherboard bios. His went from 47 down to 42 no matter what. Now he is rocking 50x100 at 5.0ghz

bennoculus · Nov 20, 2011

CalsonicGTR said:
Ok I disabled all of the C States (C1E, C3, C6) and Speedstep and tried again. Multiplier still fluctuates. Temps hit a max of 61/66/63/61 for all 4 cores with a 1.28 VCore. Im, using a Hyper 212+, are these temps high enough to activate the thermal throttling?

Nope they are not. You need to be above 90C to throttle.

aaawew · Nov 20, 2011

CalsonicGTR said:
Ok I disabled all of the C States (C1E, C3, C6) and Speedstep and tried again. Multiplier still fluctuates. Temps hit a max of 61/66/63/61 for all 4 cores with a 1.28 VCore. Im, using a Hyper 212+, are these temps high enough to activate the thermal throttling?

I had this problem too, try disabling spread spectrum i think this is what solved the problem for me

Neuromancer · Nov 20, 2011

Dougshell said:
bud had the same issue, tried a million settings and it ended up being a well known bios issue. Update fixed it (actually a roll back) this was on a MSI GD80 (B3)

Check your motherboard bios. His went from 47 down to 42 no matter what. Now he is rocking 50x100 at 5.0ghz

I ran into it on MSI too had to do with "overclocking enabled" setting or something that was not working.

On asustek boards, sounds more like you are hitting current limits, not thermals. You can try setting current limits to 1110-120% of physically entering AMPs in the long/short mode of the turbo advanaced menu.

aaawew · Nov 20, 2011

CalsonicGTR said:
Ok I disabled all of the C States (C1E, C3, C6) and Speedstep and tried again. Multiplier still fluctuates. Temps hit a max of 61/66/63/61 for all 4 cores with a 1.28 VCore. Im, using a Hyper 212+, are these temps high enough to activate the thermal throttling?

The multiplier should not go to x16 if you have disabled C states, C1E, C3, and C6 and speedstep. as for it going from 42-38 that problem like i said above should be fixed with disabling spreadspectrum

YOO · Nov 20, 2011

sorry if hijacked this thread but i just notice i have the same problem as CalsonicGTR. i have the same board but its just a full atx.

i do have all C states disabled, turbo disabled, spreadspectrum disabled, and speedstep disabled.

did the maximum test with IBT and multi drops to x34

. any more ideas? this is my first OC.

EDIT: core current limit is at 150. gonna try 200. ill be back with results

it didnt work. im out of ideas

wingman99 · Nov 21, 2011

What's your temp under load.

aaawew · Nov 21, 2011

YOO said:
sorry if hijacked this thread but i just notice i have the same problem as CalsonicGTR. i have the same board but its just a full atx.

i do have all C states disabled, turbo disabled, spreadspectrum disabled, and speedstep disabled.

did the maximum test with IBT and multi drops to x34 . any more ideas? this is my first OC.

EDIT: core current limit is at 150. gonna try 200. ill be back with results

it didnt work. im out of ideas

So you tried disabling spread spectrum and it still dropped? (i set all the core current limits to 300 along with the CPU max core or what ever that setting is)
When I get home and look at all of my notes from trying overclocks and see what i have disabled and see if i can figure out what fixed my multiplier from dropping under load

manu2b · Nov 21, 2011

^^ Set power limit to manual and then short and long duration to 300 and you'll be good to go.
Set core current limit to 300 as well.

YOO · Nov 21, 2011

my temps are in the low to mid 60's under load. i set current limit to 300 but i could not find power limit on bios. unless, it is called something else in mine :shrug:

aaawew · Nov 21, 2011

YOO said:
my temps are in the low to mid 60's under load. i set current limit to 300 but i could not find power limit on bios. unless, it is called something else in mine

Do you see turbo boost power limit? it should be set to auto and if you set it to manual it should give you two options, long duration power limit and short duration power limit

manu2b · Nov 21, 2011

Look at the link below:
http://i303.photobucket.com/albums/nn123/nanoprobe/110625165542.jpg

Set turbo boost power limit to manual, and both short and long duration to 300

YOO · Nov 21, 2011

ok, i enabled speedstep and found turbo boost power limit and set it to manual.
set long and short to 300. gonna test!

edit: tested with those settings and stays at 42x. it does go back to x16 after is done. normal? i thought disabling C states would make it stayed OC.

one other thing, i was checking my temps while stress testing with HWmonitor and the temp would fluctuate from like 62c to 71c on all cores. which temp is right?

manu2b · Nov 21, 2011

It's normal that it goes back to 16x, that's some power saving option (speedstep actually).

Temps fluctuate, that's normal. And they are different from one core to the other.
Ideally a 5°C range, but that can reach 10°C.

The better the TIM apllied and the heatsink seated, the lower the delta between cores, but you'll always get a 4/5°C difference.

YOO · Nov 21, 2011

well so far so good. i did notice that when i run IBT core temps go up to 70c. and, when running prime95, temps stay around 60c. im guessing IBT is more stressful on cpu?

Theocnoob · Nov 21, 2011

YOO said:
well so far so good. i did notice that when i run IBT core temps go up to 70c. and, when running prime95, temps stay around 60c. im guessing IBT is more stressful on cpu?

Yes IBT is 10 degrees or so more stress almost than P95 if you set IBT on high. This is normal.

Update to the latest bios and just follow the advice as it comes. Sounds like you're well on your way to a solution and understand what's goin on :thup:

Overclocking 2500K, trying to understand weird behaviour

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