CPU multiplier low under load
CPU multiplier low under load
I'm trying to overclock my CPU from 4.7 GHz to 4.8 GHz or higher.
My PC runs fine on 4.7 GHz, stress test and all. When I put the multiplier on 48 it still at first sight runs fine but then when I benchmark I get a lower mark than on 47 and see that when under load the multiplier doesn't go above 45. The weird thing is that when the CPU is idle the multiplier does reach 48. I've tried playing with the ring multiplier and with the voltage but to no effect.
Anyone any idea what might be the issue here?
Details:
CPU: Intel i5 6600k
BIOS is up-to-date
This seems to be an unstable overclock attempt. What tool are you employing for this? I experienced stability problems with Intel Extreme Tuning Utility but not with Gigabyte BIOS. With IXTU, it only reached 100mhz at the set frequency, yet it still worked. It might be that your processor isn't capable of safely exceeding 4.7ghz. The default turbo is just 3.9ghz, so going beyond is already risky. You may eventually need to boost voltage excessively, which could damage your CPU. Increasing the Vcore to over 1.4V for that Intel i5 6600k is usually not advisable, particularly considering its lifespan (even with proper cooling).
Are you keeping an eye on the heat levels? Your performance might slow if the power isn't right.
Which tool are you testing for accuracy?
I keep track of the temperatures, and they always stay under 65 degrees, so I don't think it causes throttling. And I rely on CPU-Z's stress/bench tool—it's not super precise, but it's useful for quickly checking if an overclock performs well or remains stable.
What are your complete system specifications?
What voltage configuration is being used for a 6600K to achieve 4.7-4.8GHz operation while maintaining a temperature below 65°C? That's quite remarkable (if it holds).
Based on my experience, CPU-Z stress will only identify the OC processes that are already on the edge of instability. For better results, I recommend using tools like OCCT, Aida64, or older versions of Prime95.
CPU: Intel i5 6600k
GPU: NVIDIA GTX 1080
Motherboard: MSI Z170M Mortar
CPU Cooler: Corsair Hydro H55
Operating conditions: 4.7 GHz at 1.425v atm
Tried Aida64 as recommended, encountered an unusual situation. If I only stress the CPU, clockspeed stays steady at 4.7 GHz, but if I also check the FPU, it drops to about 3-3.5GHz—possibly normal. Also, temperatures never went above 60 degrees during testing.
This seems to be an unstable overclock attempt. What tools are you employing for overclocking? I noticed stability problems when using Intel Extreme Tuning Utility, but not with Gigabyte BIOS. With IXTU, it only reached 100mhz at the frequency I set, yet it still worked. It’s likely your processor can’t safely exceed 4.7ghz. The default turbo is 3.9ghz, so going beyond that is already risky. You may eventually need to boost voltage excessively, which could damage your CPU. Running over 1.4V Vcore for an Intel i5 6600k is usually dangerous, particularly for long-term reliability (even with proper cooling).
What settings are you applying for Uncore and Cache? You’re probably aware they should stay within 200-300mhz below your core clock. If stability remains an issue, adjusting them might help.
There’s also the concept of the silicon lottery—some chips have limitations on what they can achieve. Your processor is already doing well, so pushing it further may not be beneficial.
It's just a suggestion, but I believe you're facing the same problem as me. My performance is at kindergarten level, I run at 4.2ghz and rendering speed remains the same or worse than 3.9, regardless of voltage. Likely the issue is due to "an expert would know" reasons.