HANDS ON GUIDE

Step 4: Vcore

After saving and rebooting, I still had the same problem, and after some investigation, found the cause: not enough voltage. The faster a CPU runs, the more fuel it needs, so when overclocking, you often need to bump up the CPU's voltage. Modern motherboards offer fine control of the incoming power to the CPU, but you'll spend most of your time with the vcore.

Tinkering with voltages is the most dangerous aspect of overclocking. Overvolting components will cause them to produce more waste heat, so it's vitally important that you use good cooling - not only for the CPU, but also for the case, as overvolting will also put extra strain on the motherboard's voltage regulators. Reference CPU coolers aren't designed for overclocking, so if you're using one of these HSFs, we don't recommend increasing the CPU voltage by more than 5 per cent. A top-quality HSF, such as Arctic Cooling's Freezer 7 Pro, should allow you to increase the CPU voltage by 10-15 per cent.

However, if you need to blast more juice into a CPU, you should make the leap to water cooling. If you have powerful dual or triple-fan water cooling, or phase-change cooling, you can go higher (much higher, in the case of phase-change cooling), but you do so at your own risk.

There's no hard and fast rule about the amount by which you can increase voltages, as it depends on your cooler, motherboard, and also which CPU you have, as different CPUs have different core voltages. It's easy to find out the core voltage of your CPU, as your BIOS usually monitors it in the same place it monitors temperatures. The P5K Premium reported that it was running my Q6600 at 1.288V, so I bumped it up to 1.3V and the PC booted.

Problem alert: Don’t whack an extra 15 per cent of voltage into your CPU right from the outset. Step up the power incrementally in the smallest stages that the motherboard’s BIOS allows. Also, like endless sequels, increasing voltages provides diminishing returns. Pumping too much voltage into the CPU will make it unstable and eventually cause the PC to freeze at the boot-up stage.

Another factor is something called vdroop, which is a drop in voltage caused by overworked or substandard power circuitry. The amount of droop depends greatly on the quality of your motherboard's power circuitry and how well it's cooled, as more heat means higher electrical resistance and lower efficiency. Cooling the voltage regulators may help to achieve a higher overclock, although buying an overclockers' motherboard with high-quality power circuitry may be the only way forward.

The quality of your PSU is also extremely important. As the CPU voltage is derived from the 12V rail(s), overvolting will draw more current from the PSU at this voltage.

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