Gigabyte's GA-P55-UD6 motherboard
Two channels, six slots
The GA-P55-UD6 tops Gigabyte's P55 lineup, and with a suggested retail price of $250, it had better. This makes the UD6 the priciest of the three boards we're looking at today, although it's not substantially more expensive than the P7P55D Deluxe. Like Asus, Gigabyte also has a varied array of cheaper P55 models, including more affordable SLI-certified variants, one of which has a microATX form factor. We'll be getting to those boards soon, reserving our focus today for the UD6.
Gigabyte has made its trademark turquoisey-blue work with the more restrained motherboard aesthetics that have taken hold as of late. The UD6 certainly looks sharp, even if the racing stripes are a little odd. I'm usually a sucker for racing stripes, but these ones don't really match or line up with each other.
A more traditional heatsink layout makes the UD6 look like it's hiding typical north and south bridge chipset components. The P55 PCH is actually in the middle of the board where you might otherwise expect to find a north bridge chip. What looks to be a south bridge cooler is just covering a couple of auxiliary storage controllers. Gigabyte says this extra heatsink is there primarily to draw heat away from the chipset; the SATA chips don't produce much heat on their own.
The UD6's extensive array of heatpipe-linked coolers certainly contributes to the board's crowded look. Also crowding the layout is an extra pair of DIMM slots, making a total of six, just like most X58-based mobos. You're still limited to two channels and a maximum of 16GB of memory, but the extra slots at least make it possible to hit 12GB using relatively affordable 2GB sticks.
Like the other boards we're looking at today, the UD6 uses high-quality MOSFETs, chokes, and solid-state capacitors. As a member of Gigabyte's Ultra Durable 3 family, its circuit board is also laden with two ounces of copper. This is an eight-layer design, as well.
Gigabyte corners the CPU socket with a whopping 24 power phasesmore than either of the other boards. The UD6 is smart enough to dynamically scale the number of power phases based on system load, too. However, the sheer volume of power regulation circuitry, combined with the close proximity of the DIMM slots and chipset cooler, makes for a more cramped socket than the other boards.
Moving south brings us to a total of ten edge-mounted Serial ATA ports. Six are supplied by the P55, while the other four are tied to auxiliary GSATA and JMicron silicon. Gigabyte had originally intended to equip the UD6 with a 6Gbps SATA controller from Marvell, but problems with the chip forced its replacement.
Obviously, these edge-facing ports won't interfere with longer graphics cards. However, if your case's hard drive cage happens to snug up right next to the motherboard tray, you might have to get creative with SATA cabling.
In case you're wondering, that's a CMOS reset button near the front panel connector block. I'd rather see this button in the port cluster where it can be accessed without popping case panels, but at least you won't have to fiddle with a jumper.
The UD6 has the same slot complement as the Asus board, but Gigabyte stacks things in a different order. A potential conflict between DIMM slot retention tabs and longer graphics cards is avoided by putting the top x16 slot one down the line. However, the top x1 slot doesn't have much clearance for longer expansion cards. The proximity of the chipset cooler even creates problems for my tiny x1 Gigabit Ethernet card.
Fortunately, the rest of the UD6's slots are spaced intelligently. The board doesn't feature an nForce 200 chip, but you do get a third x16 slot. This slot shares bandwidth with the x1s and the Serial ATA controller used to drive the eSATA ports, so you only get the full four lanes of bandwidth if you're willing to give up the other stuff. Those who'd rather have all of the UD6's x1s and peripherals active can switch the x4 to single-lane mode in the BIOS.
I'm not sure Gigabyte could've squeezed more into the UD6's port cluster if it tried. There's plenty of everything, including dual FireWire ports and a pair of digital S/PDIF outputs. More importantly, those ports are driven by Realtek's ALC889A audio codec, the only one capable of encoding multi-channel digital bitstreams on the fly. Real-time encoding isn't necessary for movie playback, but it's the only way to pipe multi-channel game audio through a digital output.
The port cluster has a whopping eight standard USB ports, plus two more in hybrid eSATA/USB ports. New eSATA devices are apparently on the way, and they'll be able to pull power from these ports, eliminating the need for inconvenient wall warts or auxiliary power cables.
Like most Gigabyte boards, the UD6 features dual BIOS chips. One serves as a handy backup, and the capacity of the chips themselves has been increased with an eye towards eventually storing crash information for troubleshooting purposes. For now, you can use the extra capacity to save passwords and "important dates" if you want those stored on your motherboard's BIOS chip for some reason.
The BIOS itself is loaded with overclocking and memory-tuning features, including per-channel timing controls. Most high-end motherboard BIOSes let you arbitrarily key in values for clock speeds, voltages, and timings, and so does this one.
The UD6's fan speed controls are sorely lacking, however. There's no option for temperature-based control for the system fan header, and the CPU fan speed options are even more limited than on the Asus board.
Oh, the tinfoil hat crowd should probably be aware that the UD6 sports a TPM chip. Worry not, though; it can be disabled in the BIOS. The chip's encryption key can be housed on a USB storage device or even a cell phone, should you wish to tie access to your data to either device.