ASRock M3A785GXH/128M: BIOS And Overclocking
A list of voltage and frequency ranges can be found on page 21 of this review.
Even though the 785G isn't what we'd call an enthusiast chipset, ASRock takes this board seriously when it comes to BIOS tweaking options. In fact, this is the only board in our roundup that allows for dedicated integrated GPU voltage adjustment instead of making users rely on the generic northbridge voltage alone. It features three BIOS profiles, a BIOS flash utility, and AMD's Advanced Clock Calibration (ACC) feature. The only notable missing adjustment is the southbridge voltage. We found that AMD's own overclocking tool didn't operate very stably on the ASRock board, so relying on the BIOS to tweak the settings was preferable.
It seems that ASRock is the only manufacturer that actively advertises AMD's ACC feature as a potential way to unlock dormant CPU cores or enable dormant cache. This is a very hit-or-miss capability though, largely dependent on your processor. Indeed, turning on ACC allowed us to turn on disabled CPU cores, thus enabling the fourth core in our Phenom II X3 705e. Unfortunately, our Phenom II X2 550 CPU did not grace us with the same experience, and turning ACC on simply crashed the system. This can be a blessing or a curse—while the feature could enable dormant CPU cores, it can't be used to increase overclocking success with CPUs lacking viable dormant cores or cache.
Overclocking the integrated graphics core was very successful, and we enjoyed a clean 100% overclock to 1 GHz from the stock 500 MHz. To do this, we had to raise the mGPU voltage a little to 1.59V, which is a dedicated voltage setting that no other 785G board in this roundup had.
In fact, our only disappointment was memory support. We couldn't boot our Mushkin XP3-12800 at 1,600 MHz using relaxed 9-10-10-25 timings, even though this memory is sold as a 7-8-7-20 part. We know that it's difficult to get AM3 CPUs working with memory speeds faster than 1,333 MHz, but since ASRock proudly advertises 1,600 MHz memory support on the box, we had higher expectations. Despite this issue, AM3 processors will probably prefer low-latency 1,333 MHz memory over 1,600 MHz memory anyway, so this is more of a disappointment than a serious performance detriment.
In summary, the ASRock M3A785GXH/128M is a full-featured board that facilitates lots o flexibility for the enthusiast on a budget.