Power Consumption and Overclocking
Despite the APU's high 100W TDP rating, it came out as one of the better performers in our power consumption tests. When we previously tested the Llano APU, we found that generation of APUs fell behind in terms of power consumption. Now with Trinity, we can safely say that the move to the new Piledriver architecture has addressed some of those issues.
We overclocked the AMD A10-5800K by manipulating BIOS settings, thus bypassing the AMD Overdrive software as we prefer the simplicity of the former. We approached on two fronts, first, we left the frequency of the Northbridge at its default of 100MHz and pushed the APU Multiplier to 46 (the highest we could reliably push) to obtain an overclocked APU frequency of 4.6GHz. This was achieved by turning off AMD Turbo Core 3.0 (in the ASUS UEFI utility, this corresponded to the AMD PowerNow setting) and we also turned off the C6 Mode function. Last of all, we had to crank up the CPU Core voltage to about 1.63V using an Offset Voltage of about 0.1375V.
Next, we also tried our hand in overclocking the NB frequency to 105MHz and managed to push the APU multiplier to 42, the highest we could go to obtain a stable overclocked state. Hence, in this case, the net overclocked frequency was approximately 4.4GHz. Both overclocked settings were obtained from air cooling.
For the Cinebench 11.5 benchmark, our overclocking efforts translated to a small gain in the range of about 9- to 11%, which is somewhat in-line with the frequency increase from a base of 3.8GHz (or just over 4GHz when in turbo mode). For its CPU Score in the 3DMark Vantage benchmark, the gain was much less at just 1.8- to 4.2%. Similar margins were seen in Far Cry 2. In the end, it seems that overclocking only yielded a small gain, though the best case scenario did match up in scaling with the increase in frequency. Is it worthwhile to pursue? While the actual improvements are small, let's just say if there was perhaps another SKU like an A10-5900, our overclocked performance should probably match this theoretical APU model.