AMD 770X Motherboard Duel

Stability

Testing both these board's stability has tested our mental stability as much as their construction. Initially we started graphics testing these boards using older 8.4 Catalysts for multi-GPU performance, and met with enormous difficulties with the Abit AX78. Random crashes were common place, under absolutely any circumstances, and our overnight stress test failed before we'd even left the office.

However, the difference brought by the recently released Catalyst 8.6 drivers has been amazing, and has turned the Abit AX78 from a jittery nightmare to a fairly solid board. With Catalyst 8.6 installed, and a dual Radeon HD 3850 in CrossFire configuration, it returned a fair result in our 24 hour Prime95 and 3DMark06 hardware torture test, with Prime95 crashing after 3 hours, but 3DMark06 going the distance and completing the full 24 hours of the test.

Likewise, the Sapphire board was also unable to complete our full torture test, with Prime95 crashing after a few hours and 3DMark06 continuing on for the full 24 hours of the test.

While perhaps not rock solid under heavy CPU load, the fact that 3DMark ran for the full 24 hours on both boards proves that despite their budget price tags, the AMD 770X chipset is a pretty solid base for CrossFire graphics solutions, however we wouldn't recommend relying on either of them absolutely.

Overclocking

Our attempts to overclock these boards met with very mixed success. Unsurprisingly given Abit's heritage and with its significantly more comprehensive BIOS, it was very simple to overclock, and happily reached a CPU HTT clock of 250MHz, resulting in a CPU speed of 3GHz. This was achieved with just minor additions to the core and north bridge voltages, while only having to drop the memory to DDR2-800. When we did push the board too high, the ability to easily clear the CMOS from the switch on the rear I/O was a great inclusion and worked perfectly.

On the other hand, the Sapphire board was another experience entirely, and soon proved itself a very poor overclocker. After much trial and error, we were able to squeeze the CPU clock up to 230MHz, but only after dropping the memory right down to DDR2-667, and making notable voltage alterations (well, what we could given the limited BIOS options). This was very disappointing, as we know from past experience, that while Phenom doesn't overclock particularly well, the 8750 processor we tested in other boards will comfortably reach 3GHz. This poor overclocking performance was certainly a surprise considering the extra PWM and solid state capacitors that the AM2RX780 possesses over the AX78.

Conclusions

Unfortunately our overall feeling is that both these boards have been a disappointing to review, especially as we had such high hopes for AMD's inexpensive 770X chipset.

The AX78 was going to be disadvantaged from the start, with its second PCI-Express x16 lane limited to just x4 bandwidth, and sure enough it was resoundingly beaten by the Sapphire in every single multi-GPU test by a significant margin. Its single card performance was mediocre, and while better than the Sapphire in some tests, was equally beaten in just as many.

However, despite these disadvantages, Abit has obviously tried hard to do the best it can to a strict cost, and features like the onboard post display, a clear CMOS switch on the rear I/O, as well as heatpipes based on the north bridge and PWM cooler are all inclusions we'd have expected on a much more expensive board. Abit's BIOS was also impressive considering the price tag, and our reasonable overclocking experience with the board reflected this.

Sadly, the Sapphire AM2RX780 was the real disappointment in this test. Despite comparable single GPU performance (following a BIOS flash to get Crysis to run) to the Abit, and massively superior multi-GPU performance, the Sapphire is under featured in comparison, and our experience with it has suffered as a result.

The AM2RX780 also suffers from poor board design, with a dual slot GPU in the primary PCI-Express slot obscuring half of the four SATA ports, and a reduced ATX board size resulting in worrying bending of the board when fitting the 24-pin and IDE cables. The BIOS was also poorly featured, and despite the superior materials used in its construction, the AM2RX780 achieved a very poor overclock in comparison to the Abit. Heck, even the included driver CD was rubbish, with absolutely no support for Vista 32 or 64 bit!

Final Thoughts

Our conclusions on these boards stem from the approaches their manufacturers seem to have taken towards them. Abit has been given AMD 770X and tried hard to make a functional, attractive and tweakable motherboard, and despite poor multi GPU performance from the frankly pointless second PCI-Express x4 slot, it has made a board that has a few desirable high end features and overclocks relatively well. At less than £50, it represents a solid attempt at building a well featured budget AM2+ board, just as long as you don't want to bother with CrossFire.

Sapphire has taken the same budget chipset, and surrendered to its low cost nature. Bar the solid state capacitors, cost saving steps have been made all over, from the reduced board size, resulting in cramped SATA ports, to a simplistic cooling solution and an under featured BIOS, the signs are everywhere that this is a budget board. While no price has been confirmed for the AM2RX780 as of yet (we're still waiting to hear back from Sapphire with final details and we'll add an addendum once the price has been confirmed) its rumoured to launch at £60. In its current state it would be difficult to recommend at even £50, and compared to the AX78 seems very poor value unless you're planning on building a CrossFire based PC.

Abit AX78

• Features
• x
• x
• x
• x
• x
• x
• x
• -
• -
• -
• 7/10

• Performance
• x
• x
• x
• x
• x
• x
• -
• -
• -
• -
• 6/10

• Value
• x
• x
• x
• x
• x
• x
• x
• x
• -
• -
• 8/10

• Overall
• x
• x
• x
• x
• x
• x
• x
• -
• -
• -
• 7/10

Sapphire AM2RX780

• Features
• x
• x
• x
• x
• x
• -
• -
• -
• -
• -
• 5/10

• Performance
• x
• x
• x
• x
• x
• x
• x
• -
• -
• -
• 7/10

• Value
• x
• x
• x
• x
• x
• x
• -
• -
• -
• -
• 6/10

• Overall
• x
• x
• x
• x
• x
• x
• -
• -
• -
• -
• 6/10

What do these scores mean?