A Trend Toward 2 Ounces
As mentioned, the P55-UD6 is another Ultra Durable 3-based design with Gigabyte's touted two ounce copper power and ground motherboard layers (the -UD6 is an eight-layer PCB). We've had a hard time quantifying the benefit of this addition in the past, since the benefits are said to be lower temperatures thanks to lower impedance, but perhaps the greatest evidence that there's some meat behind the marketing is the fact that Asus is also onboard the two ounce copper train (and indeed implemented this on an older workstation board).
More Power Circuitry
A complex 24-phase VRM means that there isn't enough room on the top of the motherboard for all of the circuitry. A slew of MOSFETs and Intersil phase doublers constitute the backbone of Gigabyte's solution, generating 24 phases with 12 PWM inputs. It is, perhaps, notable that the VRM circuitry on the bottom of the board isn't cooled by an elaborate heat sink/pipe, suggesting that expensive power circuitry cooling is likely over-the-top for most Core i5-based platforms.
Eagerly Awaiting P55-UD6
Gigabyte employs a familiar layout, but not one we've yet seen from a P55-based platform. Asus and Gigabyte drop the single-chip chipset behind the expansion slots on their less-expensive offerings. However, because Gigabyte's original plan accounted for three SATA controllers down there, the -UD6 features its P55 right where you would have expected to find an X58 or P45 northbridge.
A heatpipe connects the P55's passive cooler to what appears to be a southbridge heatsink. But because the two Marvell 6 Gb/s SATA controllers were scrapped, there's a fair chance that this board's cooling solution will change before it ships.
P55 Goes Value-Oriented
Taking a step down Gigabyte's P55 family results in a completely different board design, but a functionally-similar offering--great news for the value-oriented folks who'd like to save some money, but still buy a solid motherboard.
Let's take a look at Gigabyte's P55-UD4P. First, though: what differentiates the -UD4P from the planned -UD4 model? As far as we can tell from the proposed specs, the -UD4P has a Trusted Platform Module, whereas the -UD4 does not. That seems to be it, though.
Back To Basics: The P55-UD4P
Put side-by-side with the EP55-UD6, the -UD4P looks quite a bit different. But the two boards actually share a lot of core functionality in common.
Still Lots Of Rear IO
The similarities are apparent beginning with the rear I/O panel. This time, however, you get 10 USB 2.0 ports back there, the same single PS/2 port, two digital audio connectors (optical and coaxial), a pair of FireWire ports, two eSATA connectors, twin 8P8C jacks, and a full complement of 1/8" mini-jacks.
Enough Expandability For Almost Anyone
Gone is the third PCI Express x16 slot. Instead, the P55-UD4P includes two x16 slots (which run at x8 signaling rates when you're using a pair of cards in either SLI or CrossFire), two standard PCI slots, and a trio of x1 PCIe slots.
There are no worries about outstripping the chipset's PCI Express capabilities on this one. Between the three x1 slots, a Marvell storage controller, a JMicron storage controller, and two Gigabit Ethernet controllers, the P55-UD4P utilizes six of the P55's eight available links.
Still An Engineering Sample
Perhaps you looked at that three-quarter shot a few pages back and wondered why the P55-UD4P had a passive heatsink layout similar to the -UD6. Proof that these boards are still early samples, the sink covering the area where you'd normally expect to find a northbridge isn't actually covering anything. Rather, the P55 PCH sits behind the board's expansion slots.
Gigabit Ethernet
Like the P55-UD6, this motherboard boasts a pair of Gigabit Ethernet controllers. Gigabyte's official spec sheet says the final board will include two Realtek 8111D controllers, which support jumbo frames. But the early sample we shot here is still rocking the 8111Cs.
High Def Audio
It's hardly a surprise to find Realtek's ALC889 High Definition Audio codec onboard. But we did think it was worth noting that this codec specifically is one only two able to output two channels of 192 kHz/24-bit or 4-8 channels of 96 kHz/24-bit audio when used in conjunction with Cyberlink's PowerDVD 9.
