Now that 4.7 GHz is stable and I've determined the limit out of the cache, it is time to nudge it further. This will be tiny steps, but with a 50% overclock at arm's length, this is hopefully going to be a fruitful endeavor.
Let's recap what we've set so far to reach the 4.7 GHz:
- CPU Ratio - All Core
- BCLK - 100.0
- Spread Spectrum - Disabled
- Intel SpeedStep - Disabled
- RAM - XMP Profile 1 (DDR3-1600 9-9-9-24 1.35V)
- CPU Vcove Voltage Mode - Override
- CPU Voltage Fixed - 1.30V
- FIVR Voltage Fixed - 1.90V (input voltage)
- CPU Cache Ratio - 45x
- Filter PLL Frequency - High BCLK Mode
- Internal PLL Overvoltage - Enabled
- PCIE PLL Selection - SB PLL
- System Agent Voltage Offset - 0.200V
- CPU analog IO Voltage Offset - 0.200V
- CPU digital IO Voltage Offset - 0.200V
- FIVR Efficiency Mode - Disabled
This still leaves some options. I have yet to touch CPU Load-Line Calibration because I need to look into it to find out how this works on this particular board. I can also adjust the BCLK to improve overclocks but it involves a lot of other aspects like the RAM which in my build is not meant for overclocking.
For now I'm going to try to focus on achieving the highest Core clock I can, beginning at 4.8 GHz.
Remember in the earlier test: 48x100 at 1.30V --- No boot/POST
Currently it's purring at that setting 15+ minutes in AIDA 64's System Stability Test, before I unleash the relentless Prime95 onto it. But as you may have noticed, this means that 4.8 GHz is possible to achieve, even though it seemed not to be at all possible when just adjusting the Core Voltage.
Third step: Nudging
- 48x100 at 1.30V and Cache Ratio x45 --- 75-80°C - few minutes of Prime95, BSOD
- 48x100 at 1.325V and Cache Ratio x45 --- 77-82°C - Passed: 640K, BSOD
- 48x100 at 1.325V and Cache Ratio x44 --- 77-82°C - Passed: 640K, BSOD
At this point I'm not seeing much stability with 4.8 GHz so it might as well be that we've reached the limit with air-cooling or possibly this board. We shouldn't forget 82°C is close to the CPU's limit so even more voltage is not going to get us great results either way. Lets not forget at 1.30V we have increased the voltage with 30% already.
After reviewing some settings, I've noticed I had analog and digital voltage set, although this should only matter for RAM overclocking. I've also slightly increased the System Agent Voltage offset to 0.250V as a gut feeling.
I've seen others also topping out at 4.7 GHz, with roughly the same settings. This might mean we're hitting a wall somewhere, which I'm too inexperienced to be making guesses at. So instead of reaching for the stars, lets find a more comfortable setting by slowly reducing the voltage and see how low I can go to attain the maximum clock rate.
- 47x100 at 1.300V and Cache Ratio x45 --- 75-80°C - ~1 hour of Prime95, moving on
- 47x100 at 1.275V and Cache Ratio x45 ---
