8086k overclocking adventure on air

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VoodooRufus

Weaksauce
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May 23, 2017
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So I got new toys to play with. Gigabyte Aorus Master mainboard, Intel 8086k delidded Silicon Lottery CPU, using a Dark Rock Pro 4 heatsink.

I left everything on auto, set the CPU wattage limit to 250W, and then started jacking up the multiplier. The mainboard automatically ramped CPU voltage depending on the clock rate, pretty aggressively once I got past 4.6GHz. Did some 30-45 minute prime95 runs to test initial stability. I manually played with the fan settings to get a good balance of noise/airflow/temps. After 70C I have the CPU and chassis fans running 100%, which is still a low hum. Anything under 60C is nearly silent.

Anyway, on 5.0GHz I needed 1.32V in bios (LLC set to 6) to get it stable in a short term sense. I had it crash out a few threads after 6 hours. What puzzles me is that depending on the P95 task type, the CPU will either stay nice and happy around 65-70C and a calculated HWMonitor CPU wattage of 150W, or ramp up to 200W and 85-90C (ouch), like a switch. It will bounce between the two every 15 minutes or so. The clocks are not throttling, but the VID drops from 1.35V to 1.28V, while the Vcore maintains at 1.36V.

What's going on here with the temp and wattage switching?
 
VoodooRufus said:
What's going on here with the temp and wattage switching?
Click to expand...

You are experiencing an AVX workload in P95 which will increase temps and wattage when it is ran. When those threads crash, it means your OC is not AVX stable at those clocks, but are stable in non-AVX loads. You should have a AVX offset setting in your BIOS, which down clocks your CPU when AVX is ran. You can disable it or run a version without AVX (26.6), if you feel that you will not use AVX in you everyday usage. AVX is starting to be used more and more in games and programs. It has been on Intel CPU's since Sandy Bridge.
 
I'm now running a 500MHz offset on the AVX offset and it will still spike to 85c resulting in a BSOD, lockup or reboot. Non-AVX runs solid at 5.0GHz. Right now I'm at 1.32V. I tried 1.35V, lowering the wattage target for the CPU, and maximizing the LLC to no avail.

AVX is a total pain. I'm using Boinc SETI as my overall system load. Tempted to disable AVX on the optimizations since the GPU does most of the heavy lifting on SETI these days. Either that, or see what my custom water loop gear can do on this chip.
 
The Dark Rock Pro 4 is a pretty good HSF, so depending on the silicone lottery with your particular chip, a custom loop could be just what the doctor ordered to get you past that AVX wall.

Then again 85c isn't that bad for that chip, I've seen way worse. Granted AVX is a bitch to get stable, but you could be just hitting the limits of the silicone, even @ 500MHz offset.
If you have the parts ready to slap on just laying around, I would go for it.
 
The CPU was acquired through SiliconLottery, a re-lidded unit binned for 5.2GHz at something like 1.45V (ouch), and a AVX offset of 4. Not sure how much effort they put into fine tuning the voltage.

I am amazed how effective the DRP4 heatsink is, especially for the noise levels.

All I need is a pump again, and I can get my custom gear put in. I got an EK DDC bayres combo, but it's pretty noisy. My old Koolance DDC was near silent sitting on a Shoggy Sandwich in comparison (it died). Might go for a D5 PWM and see how far they've come in 10 years.
 
VoodooRufus said:
The CPU was acquired through SiliconLottery, a re-lidded unit binned for 5.2GHz at something like 1.45V (ouch), and a AVX offset of 4. Not sure how much effort they put into fine tuning the voltage.

I am amazed how effective the DRP4 heatsink is, especially for the noise levels.

All I need is a pump again, and I can get my custom gear put in. I got an EK DDC bayres combo, but it's pretty noisy. My old Koolance DDC was near silent sitting on a Shoggy Sandwich in comparison (it died). Might go for a D5 PWM and see how far they've come in 10 years.
Click to expand...

Wow. She's a voltage whore for sure. Grab a D5 and try to tame that beast.:)
 
CAD4466HK said:
Wow. She's a voltage whore for sure. Grab a D5 and try to tame that beast.:)
Click to expand...

Yeah get all you can out of that chip since you paid the SL premium. The custom waterloop should get the job done. I use 1.4V 5ghz -2AVX on my 8700K. If I do no AVX offset my P95 temps are in the 90s.
 
Ordered up a pump last night. Still gunning for "very quiet" so I went with a DDC 3.1. Block will be an Optimus V1 and the radiator a Blackice Nemesis GTX280. I have 4 Noctua 2000rpm 140mm's for push/pull, but I'll stick with the Fractal 1000rpm fans to start off with.
 
Just for baseline temps:

SSE4.2 Seti tasks and Cuda. 4.8GHz at 1.315V, -4AVX offset (not running AVX). Max CPU temps 83-85C at full fan speed, which is nice and quiet, but as good as this DRP4 can do.
 
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