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Making Lemonade: Overclocking Your Locked AMD Processor

Overclocking Via AMD OverDrive

AMD OverDrive

New users of AMD’s OverDrive may want to take a look back at this guide for a more in-depth introduction to the utility. Today, we’ll head straight into advanced mode and the Performance Control menus.

Overclocking a Black Edition processor in AOD (AMD OverDrive) is rather simple, but to get started with our locked processor, we first need to lower the NB and HT multipliers, along with the memory ratio. The CPU NB Multiplier in the Clock/Voltage tab, as well as the Memory Clock in the Memory tab are both highlighted with red text, meaning these values can only be applied with a system restart. Keep in mind HT Link speed can not be higher than northbridge speed, and changes to this “white-labeled” multiplier are not automatically applied at restart like the red values. We avoided this issue by first changing all of these values in the BIOS.

It didn’t take long to discover that changes made to the HT reference clock in AOD would not stick, even after clicking “Apply.” This can be seen by comparing the Target Speeds versus Current Speeds.

In order to proceed with overclocking, the reference clock needed to first be changed in the BIOS from its 200 MHz default. Any change would work, so we set it to 201 MHz.

Finally prepared to start overclocking within AOD, we started to raise the HT reference clock slider 10 MHz at a time. All was fine until we hit an unexpected wall at 240 MHz; from there on, the system would either lock up or reboot. Some fine tuning pinpointed the problem, allowing us to go beyond 238 MHz. The solution required setting the reference clock to 240 MHz in the BIOS. We then raised the HT reference clock 5 MHz at a time until we again ran into the same problem getting past 255MHz. After booting with a 256 MHz reference clock setting in the BIOS, all went smoothly up to the same maximum stable stock voltage overclock previously seen.

Next, the NB and HT multipliers were both lowered to 7x in the BIOS, and the reference clock was set to 265MHz. After entering the OS and AMD OverDrive, it was time to raise voltages.

Notice that, because this is a locked processor, the CPU VID slider is already maxed out at 1.3250V. To raise the CPU voltage, the CPU VDDC slider is used to apply the offset voltage. In addition to 1.504V CPU VDDC, the NB VID and NB Core were bumped to 1.25V. This allowed the HT reference clock to be raised incrementally to 288 MHz without any further issues.