Verdict: AMD's new Spider is more Incy Wincy than funnel-web.
Every now and then it's good to look back, with violins playing in the background, at some of the great products we've seen this year. Unfortunately, we can't think of a single Socket AM2 motherboard to include in that list. We were therefore eager to discover what AMD's new Socket AM2+, designed for its quad-core Phenom processors, could do. The snappily named Gigabyte GA-MA790FX-DQ6 uses AMD's new flagship 790FX chipset, too. To borrow a phrase from the Kaiser Chiefs, has AMD come back stronger than a powered-up Pac Man?
The only major distinction between the 790FX chipset and the lesser 790X used in the MSI K9A2 CF is that 790FX supports CrossFireX (for up to four HD 3-series graphics cards) and more overclocking options in the new software overclocking tool, OverDrive.
AMD states that 7-series chipsets have a TDP of only 10W, allegedly making them much more energy-efficient than Nvidia or Intel Northbridges (although chipsets for Intel CPUs also handle memory traffic, unlike their lazy AMD counterparts). This is a nice touch, as AMD hasn't skimped on features. To provide four graphics cards with respectable bandwidth, the 790FX has 40 PCI-E 2.0 lanes. With four cards in CrossFireX mode the lanes are split up so that each slot has eight lanes (the other four PCI-E lanes are used for other devices, if at all). However, despite only having eight lanes each, the slots still get 8GB/sec bandwidth, as PCI-E 2.0 provides double the bandwidth of PCI-E 1.1. With only two PCI-E 2.0 cards, each slot has 16 lanes for 16GB/sec of bandwidth. The Southbridge is the same chip that ATI boards have used for ages, the SB600.
Socket AM2+ is similar to its predecessor in that it works with any Socket AM2 CPU cooler, and, as the pin layout hasn't changed, also accepts any Socket AM2 CPU. Socket AM2+ improves upon Socket AM2 by offering dual voltage planes, so you can adjust the voltage of individual cores in Phenom processors. Two heatpipes snake around the socket from the VRMs to the Northbridge, and a third heatpipe moves heat from the smaller Southbridge chipset. For some reason, these heatsinks and heatpipes are called 'Quad Cooling' on the box. The CrazyCool backplate on the CPU socket may constitute a third type of cooling, but we're stuck for the fourth - air, perhaps?
Continuing with the quads theme, there are four DDR2 memory sockets. You could fill these with 1GB sticks to have 4GB for another quad, although the board also accepts 2GB sticks, for a total of 8GB. The box includes two backplates with two eSATA ports each, so that's quad eSATA too. Even if you use both eSATA backplates, you'll still have four spare S-ATA II headers, providing another quad. And this board supports quad-core Phenoms and four-card CrossFireX for two more types of quad. However, the 'how many quads?' game gets silly when you consider that the board also includes 'Quad BIOS' and 'Quad Double Phase' power regulation. Only a few of these quad 'features' are of any tangible use, making us wish that Gigabyte didn't rave about them quite so much.
Although the 790FX chipset supports CrossFireX, the Gigabyte's four PCI-E slots are situated very close together, which rules out using dual-slot cards. Even if you use single-slot HD 3850 cards, you'll lose access to four of the six internal S-ATA II ports.
You'll also need a PSU with four PCI-E six-pin plugs, not to mention enough wattage to power all four cards. Coaxial and optical S/PDIF outputs on the back ensure you'll get the best from the on-board HD audio.
Performance
For testing we used the current top-of-the-range £174 Phenom 9600 with 2GB of Corsair DDR2 memory and a Samsung hard disk. The system limped through our benchmarks with a poor overall score of 780 at stock speeds.
Our reference PC comprises an Intel Core 2 Duo E6750 (which costs around £113) and an Asus P5K Premium motherboard (roughly £120), plus the other standard test kit, and scores 1,000. This means that our benchmark reference PC is roughly £96 cheaper than the Phenom 9600 and this Gigabyte board. Our test system is far faster and it isn't even quad-core.
As the Phenom 9600 is a quad-core chip, we expected it to redeem itself in the encoding test. However, it scores 1,000 at stock speeds - the same as the dual-core Intel chip. Multitasking proved to be the Gigabyte's greatest downfall, though, with a score of only 627. The BIOS we tested with, however, was an early version, and Gigabyte will no doubt produce an update soon.
Overclocking should have been easy with the OverDrive tool, but it refused to run, telling us it couldn't find an AMD processor. We turned to the BIOS but, with no option to lower the CPU multiplier, we couldn't find a maximum FSB, nor could we apply any extra voltage to the Phenom. Eventually, we upped the HTT from 200MHz to 220MHz, boosting the chip from 2.3GHz to 2.53GHz. This resulted in only a tiny increase in the scores.
Conclusion
It's almost impossible to rate the Gigabyte GA-MA790FX-DQ6. It isn't Gigabyte's fault that CrossFireX and OverDrive don't work at the moment, or that Phenom is currently pretty poor.
We can only conclude that Spider isn't complete, and therefore not worth investing in yet. ATI needs to sort out its CrossFireX drivers, AMD needs to work on its OverDrive tool and motherboard makers need to work on BIOS updates for the new chipset and CPU. You'd be silly to spend £155 on a product that may improve but currently has more bugs than a David Attenborough documentary.
