Overclock stable on i7 8700k but experiencing problems
Overclock stable on i7 8700k but experiencing problems
My cooler is an Arctic Cooler i30 CO. It has been functioning well for a long time and supports up to 160 watts. The specifications list:
Max. Cooling Performance: 320 Watts
Recommended for TDP up to: 160 Watts
Note: I'm using prime95 on stock clock, but temperatures often exceed 82°C with the CPU VCore at around 1.123V.
It's functioning well since you rarely exceed 160w with your 8700K, except during stress tests. I'm unsure how they achieve 320w max cooling performance—it might just reflect the overall system draw, as other 320w TDP coolers I've seen are significantly bigger. Plus, if the i30 CO were truly a 320w cooler instead of 160w, you wouldn't experience thermal throttling in Prime 95 at that moment.
I see you're dealing with some persistent problems, but it started with handbrake during an overclock I've been using for a few years. At first, the machine would freeze when running handbrake at 4.8 with an offset of -30. After adjusting the offset to -20, things seemed to stabilize. However, temperatures are consistently higher than expected—not just in prime95 but across all applications. My idle temps stay around 35 to 40 on a 4.8Ghz system. I don’t stress the system much, just occasional tasks like video encoding.
Sorry, for a frequency of 4.8Ghz (offset at -20), the vcore sits near 1.23v. The package draws about 160W, with temperatures reaching 92 degrees.
This result is quite low, at least based on Silicon Lottery's binning data for that CPU model.
Silicon Lottery's statistics show:
Coffee Lake
All Core SSE Frequency
All Core AVX2 Frequency
BIOS Vcore
Capable
8700K
4.80GHz
4.60GHz
1.375V
100%
8700K
4.90GHz
4.70GHz
1.387V
Top 99%
8700K
5.00GHz
4.80GHz
1.400V
Top 83%
8700K
5.10GHz
4.90GHz
1.412V
Top 49%
8700K
5.20GHz
5.00GHz
1.425V
Top 17%
8700K
5.30GHz
5.10GHz
1.437V
Top 4%
Several factors and conditions need to be evaluated regarding core temperatures and stability. Even though the throttle reaches 100°C, it's not advised if the core temperature exceeds 85°C. Temperatures below 80°C are considered optimal. The Arctic Cooler i30 CO seems insufficient for the i7-8700K when stocked, but performs better under overclocking or with a high Package Power of 160 Watts. Although tools like HandBrake can handle AVX code, the fluctuating workload and power draw usually shouldn't surpass the stable 100% load from Prime95 Small FFTs when all AVX settings are turned off.
If the core voltage drops to just 1.23 at full load, processor wear is unlikely, which typically doesn’t start on 14nm chips until the Vcore goes above 1.4, as noted by Phaaze88. Still, motherboard VRM issues can occur, leading to inconsistent power delivery to the CPU and causing intermittent crashes or BSODs, particularly during peak loads, according to keith12 regarding LLC.
You might be dealing with memory instability, which is hard to separate from CPU problems. When BSODs happen, note the error messages and codes. Use a pink eraser to clean each module’s edge connector contacts, then reinsert or swap modules between slots. Try adjusting the memory voltage in 0.010 increments to see if stability improves. Running MemTest86 and Windows Memory Diagnostic Tool is also recommended.
TIM degradation becomes clearest under full load because of high power and heat, but it’s less apparent during idle due to lower power usage. This applies to Intel’s internal paste between the die and the Integrated Heat Spreader (IHS), which also wears out over time. In these cases, the only fix is replacing the motherboard.
Concerns about high idle temps are often raised on forums, but users frequently disagree on what “idle” really means. In Windows Task Manager, idle usage should be just 1–2% CPU; not a light task and browsing with multiple tabs open. Background processes and services usually cause spikes, fluctuations, and elevated idle temps, especially when ambient temperature is high. Many overlook ambient conditions, which can vary greatly—such as 10°C near the Arctic Circle or 40°C without air conditioning near the Equator—affecting all computer temperatures whether idle or under heavy load.
The standard for a normal room temperature is 22°C or 72°F. Including ambient temperature in system specifications helps ensure users know if their machine operates in a typical environment.
Hi,
Thank you for your response.
My room temperature stays between 19 and 22 degrees.
From what others have mentioned, I might consider upgrading to a better cooling system (such as the Noctua NH-D15) for the CPU and explore the possibilities.
I've also run memtest and everything came back normal.
I removed the heat sync and cleared everything, then reapplied thermal paste.
Performance improved by roughly 10 degrees in both idle and under load.
Handbrake now operates at 4.8Ghz with a VCore of 1.23v, maintaining a stable temperature between 72-74°C.
Idle temperatures dropped to 32-34°C.
Handbrake only reaches up to 160W during operation, which the Arctic Freezer can manage.
Prime95 still causes failure as power consumption rises to over 200W.
I plan to buy the Noctua NH-D15, just need to confirm it fits my Corsair Carbide 300r (it should).