Overclocking

We've recently put in a considerable amount of effort into overclocking AMD's socket AM3 Phenom II X3 720 Black Edition, so we're quite intimate with how it fares on the MSI 790FX-GD70, which has become our motherboard of choice in the upcoming overclocking specific article.

We could squeeze 3.9GHz on the CPU and 2.8GHz on the northbridge out of two of the three 720s we have with the extra options the MSI BIOS offers. However we had to relax the overclock back to 3.7GHz CPU and 2.6GHz northbridge in order to get it very stable and pass all our benchmarks. We thought we could keep it at a nice, round 3.8GHz - a 1GHz overclock - but this provided a little too much despite our efforts to compensate with ACC and CPU core, VDD and PLL voltages.

The other boards would also hit around 3.7GHz but were more adamant that they couldn't readily attempt to boot over this. Not only that, but even just 2.6GHz on the northbridge - something the MSI was more than happy to run with - is beyond both the Gigabyte 790FXT-UD5P and Asus M4A79-T Deluxe (at the time of writing).

1,600MHz Samsung HFC0 memory (G.Skill C7 in this case) works like a charm in this board, but after discussing further with OCZ (after testing on the next two pages) it claims 1,333MHz works better for 2.0-2.6GHz memory core clock, then over 2.8-3.0GHz for 1,600MHz or higher memory.

Customised memory timings also stick, which haven't occasionally in previous MSI boards (P35 Diamond and a young P45 Platinum are two that come to mind) - so eking out C6 or if you're extremely lucky/successful C5 at 1,333MHz is do-able.

After talking more to OCZ, it claims to only have needed an increased VDD to overclock the CPU - unfortunately we didn't see this though and a degree of offset was needed in addition to make our 720 Black Editions stable. Bearing in mind though that additional cooling must be sought with elevated VDD voltages as the heatsink will quite literally roast itself. Those interested in more detail can go visit OCZ's forum who have people with far more time than myself to eke out the specific details.

We love MSI's short overclocking guide and have reproduced it here for you to read below. MSI explains how to use its and best overvolt and overclock the HTT bus in stages that suits the board: accordingly a 720 Black Edition should do 3.87GHz with a HTT clock of 277MHz, multiplier of 14x, CPU-NB multiplier 8x and CPU voltage of 1.55V, CPU-NB of 1.26V, CPU and a HyperTransport ratio of 8x.

Addendum 10th May 2009: MSI requested we remove the images of its First Punch overclocking guide as it was designed for reviewers only, despite our insistence that it would benefit our readers. MSI exclusively revealed to bit-tech that it is keen to improve and possibly expand its overclocking guides with future motherboards.

We tested this out, but attained nothing more than the pure multiplier overclocking above. We had to tone down the CPU frequency a notch to 3.74GHz with a 258MHz HTT by 14.5x multiplier, but in compensation we increased the northbridge clock to 10x to give us 2.58GHz there. The memory was set to a nominal 1,376MHz, and the HTT was rounded off at 2,064MHz on an 8x multiplier as well.

We also put MSI's auto-overclock setting through its paces to test whether its 'Max FSB' (it means HTT clock) actually worked. In fact, it did, and very well too. Simply set the CPU voltage you want, enable the BIOS setting and restart the machine. Approximately 15 seconds later after thinking about it for a while it POSTs and you can go back into the BIOS to check the settings. On its own it achieved 351MHz HTT with a 9x CPU multiplier, and a rather tame northbridge frequency of 2,103MHz with memory at 1,400MHz CAS9. If anything, this could be used as a starting block for some - increase the voltage VDDs, and add more CPU-NB and CPU multipliers to gently easy up the total frequencies.

It's worth noting that during this overclocking research we found a rather disappointing feature on the MSI board - it doesn't seem to easily detect failed overclocks and reset itself, leaving us to have to turn it off, clear the CMOS, turn it on and reload the BIOS profile to start again. This is, at best, a labour intensive way of doing things.

Overclocked Gaming Performance

CrossFire-X responds very well to the extra CPU frequency: in Crysis and Far Cry 2 we see an extra ten frames per second on average, with a large jump in minimum frame rate for the latter, making the game much smoother. Overall we see a 30 to 40 percent performance improvement just from overclocking - a nice bundle of free performance.