Overclocking
Overclocking comparisons need to be made against other FM2 boards in this review. We've increased the CPU, DDR and GPU voltages to arbitrary levels and noted just how high each board could run the APU's various parts at.
Motherboard |
Sapphire PP A85XT |
ASRock A75 Pro4-M |
Gigabyte A85X-UP4 |
|---|---|---|---|
Max CPU speed @ 1.50V |
4.6GHz |
4.5GHz |
4.5GHz |
Max DDR3 speed at 1.60V |
2,200MHz |
2,200MHz |
2,200MHz |
Max GPU clock at 1.25V |
1,030MHz |
1,013MHz |
1,000MHz |
One aspect in which the A85X chipset is better than the A75 is with adjustments to the GPU clock. A85X provides per-MHz settings while A75 runs up in circa-50MHz dividers.
We had to increase the APU's base clock in order to push the memory above 2,133MHz - the maximum enabled in the BIOS - which is something that doesn't necessarily have to be done with other boards.
Sapphire's board manages to clock the CPU and GPU on the same test chip a little higher than competing boards, and here is how the overclocked parameters shape up in three tests.
The CPU doesn't gain a whole heap of extra performance when overclocked. The reason for this is that it runs at up to 4.2GHz via the chip's Turbo CORE when in stock-clocked mode. We switch off Turbo CORE for overclocking tests.
Higher GPU and memory speeds combine nicely to push the DiRT performance by over 10 per cent, however, and this, we feel, is the main reason to overclock an FM2 board.