Overclocking our i5-2500K is pretty straightforward because we aren’t able to get performance bumps simply by increasing the system’s base clock with Sandy Bridge processors. However, we can increase the CPU multiplier and core voltages to get a sizable increase in performance. The K series LGA 1155 processors have unlocked CPU multipliers, which seem to be the preferred way to get more performance out of these cores in turbo mode too.
The MSI UEFI BIOS has all its overclocking options located in the OC Menu, and we made the following changes before we started overclocking our i5-2500K processor using the P67A-GD65:
- Left BCLK frequency at 100
- Increase CPU Ratio (The math for overclocking our i5-2500K is very simple because we just multiply the BCLK frequency (100) and the CPU Ratio (currently 45) to get the overall CPU speed (4.5GHz)
- Manually adjusted DRAM frequency to DDR3-1600
- Adjusted DRAM voltage to 1.65v
After making the changes above in the BIOS, I began incrementally increasing the CPU ratio to test how far the i5-2500K could go. I continued to increase the CPU ratio to 45x before I noticed severe instability. After backing it down a bit, we were able to get a stable 4.290GHz overclock. This isn’t the largest overclock we have received with the i5-2500K by any means, but it is definitely nothing to sneeze at because it gives our system a 30 percent increase in performance over the CPU’s stock 3.3GHz speeds.
This screenshot was taken when we achieved a 4.290GHz overclock on the MSI P67A-GD65
|CPU Speed||BCLK||CPU Multiplier||DRAM Frequency||DRAM Timings||CPU Voltage|
|1630 MHz||8-8-8-24 1T||1.3v|