I prioritized quiet operation for the stock configuration, unplugging the side-panel fan and enabling control in ASRock's UEFI to bring the remaining coolers down in speed. The CPU's stock voltage is 1.225 V, but reported voltages within Windows fluctuated between 1.208 and 1.256 V under load using HWMonitor. There was a even more variance per core within AMD's OverDrive utility. Power-saving features and Turbo Core were enabled.
When it came time to overclock, I chose to disable Turbo Core and run the fans at 100%. By far, the loudest sound from the system was its side-panel intake, which had that aforementioned whine (rather than the expected whoosh of moving air). But a 120 mm blower pushing fresh air down onto the socket interface was comforting, so it remained.
I wasn’t expecting high frequencies from the Athlon X4 750K, since it was handicapped by a puny boxed heat sink. We lucked out, though, finding 4 GHz stable on all cores at the stock voltage setting. Thermals looked good, so I started bumping the voltage up a little at a time. Stability at 4.2 GHz only required 1.272V under load, which was achieved with a +0.048 V offset and enabling APU LLC to stabilize power delivery.
Next, I sought to maximize gains by overclocking the RAM. DDR3-1866 with CAS 9 timings required 1.625 V for stability. I bumped the CPU-NB frequency to 2000 MHz, which is a modest boost that didn't require altering the Northbridge Voltage option. Everything was tested for stability as I kept an eye on thermal margin from within AMD's OverDrive utility, as well as spot-checking the motherboard's VRM with an IR thermometer.
OverDrive reported another 25 degrees of thermal margin available under Prime95. But I wasn’t comfortable pushing higher voltages, especially with higher summer temperatures on the way. Still, I have to be happy with these results considering two of our lab's 750Ks top out just 100 MHz higher at 1.425 V and topped with aftermarket coolers.
Next, I wanted to tweak MSI's Radeon R7 265 using the latest version of Afterburner. The GPU's official limit is 1050 MHz, which I hit without the need for additional voltage. The card's memory wasn't as cooperative though, causing instability at 1480 MHz. I dialed it back down to 1450 MHz (5800 MT/s).
The final overclock was filtered through MemTest 86+, Prime95, and an hour of gaming before receiving a stamp of approval and proceeding to the benchmarks.
- Presenting Our New Budget Gaming PC
- CPU And Cooler
- Motherboard And Memory
- Graphics Card And Hard Drive
- Case, Power Supply, And Optical Drive
- Assembling Our Gaming Box
- Overclocking Our Budget AMD Platform
- How We Tested Our Budget Gaming PC
- Results: Synthetics
- Results: Audio And Video
- Results: Adobe Creative Suite
- Results: Productivity
- Results: Compression
- Results: Arma 3 And Battlefield 4
- Results: Far Cry 3 And Grid 2
- Power Consumption And Temperatures
- Performance Summary
- Can Less Funding Compete For Top Value?