Overclock your CPU

1 GRAB THE SOFTWARE

So you’ve got your system set up and running at stock. Now it’s time to crank up the volts and get that processor as high as it’ll go. First thing you need to do is download a few programs. You’re going to want to get something to provide you with a base number for performance — Cinebench R15 is quick, free and a good indicator of rendering prowess. Next up, you need a synthetic benchmark — Prime95 or OCCT are two brilliant examples of this. OCCT, in particular, also stress tests memory channels at the same time. And lastly, you need two more programs — one to measure Vcore and one to measure temperature.

We suggest CPU-Z for voltage and hertz monitoring, and HWMonitor for temperatures. Although HWMonitor also measures voltages, it’s far easier to see what you’re looking at with CPU-Z.

2 RUN PRELIMINARY TESTS

After downloading and installing your benchmarking software, you need to get some preliminary figures. It’s best to note these down, or create a spreadsheet where you can document what voltage you’re applying, to what multiplier and what your scores, temperatures and stabilities are on each attempt. This way, you won’t forget and can refer back to it later on. To begin with, open up CPU-Z and HWMonitor, then open Cinebench R15, and run the CPU test three times in conjunction [Image A]. Mark down all three of these scores, and take the average of them — this is your starting point. It’s also best to note what your maximum core temperature is; ideally, you’re looking for anything under 55–60°C. Finally, note the maximum voltage CPU-Z is registering during the benchmarks.

3 ENTER THE BIOS

Once you’ve got those early tests out the way, jump into the BIOS. We’re using the ASUS RoG STRIX X99 Gaming motherboard’s BIOS. It’s identical to the Z170 platform, as well as the other brands in ASUS’s arsenal, but with a black and red skin. Restart your system, and mash the Del key to get into the BIOS. Hit F7 to get into Advanced mode. Then head across to AI Tweaker.

4 YOUR INITIAL OVERCLOCK

Once you’re in AI Tweaker, it’s important to set up your memory so it’s running at its optimal frequencies. Hit the ‘AI Overclock Tuner’ tab, and select ‘XMP’ from the drop-down menu. You’ll want to start with an initial overclock [Image B]: Go to ‘CPU Core Ratio’ and select ‘Sync All Cores’. Input a slightly higher multiplier. So if you have a Core i7-6700K reading ‘42’, input ‘44’. Hit F10, save and reboot, then head to the desktop to see if it’s stable. At this point, it’s not worth messing with voltages.

5 THE STRESS TEST

Now repeat what you did with your preliminary tests. If the system is stable, great — you’re on to a winner. Head back into the BIOS and increase the multiplier once more. You want to keep doing this process until the system locks up.

6 INCREASE THE VOLTAGE

Now you’ve hit the limits of the base voltage, you want to start increasing the voltage to the CPU to overcome those stability issues. This is where you start to see a substantial increase in overhead temperatures. Head back into the BIOS, to AI Tweaker, then scroll down until you see ‘CPU Core Voltage’, and change it to ‘Manual Mode’. Now, with your voltage noted down from earlier, change the ‘Voltage Override’ from ‘Auto’ to a setting slightly higher than that. We suggest increasing Vcore by 0.05 at a time — do this until the overclock holds through Cinebench R15. Then it’s just a case of rinsing and repeating, slowly increasing the multiplier and Vcore side by side until the system is stable.

7 YOUR FINAL OVERCLOCK

Eventually, you reach a point where both temperature and stability become an issue. If you’ve been noting down all these figures on a spreadsheet, this’ll come in handy for the next bit. Ideally, you’re looking for temperatures around 70–80°C under load. The reality is you’ll probably hit silicon instability long before you reach TJMax. At this point, you want to dial it back down one setting to the last stable frequency [Image C]. After which, do a full system stress test by running a synthetic benchmark for anywhere from 1 to 24 hours, depending on your patience. We suggest OCCT here, because it also saturates the memory channels effectively. If you do run into any trouble, add a little extra voltage or reduce the multiplier a fraction to compensate.