Compact P55: Four MicroATX Motherboards Tried And Tested

Compact MicroATX Platforms For Core i5 And Core i3

Thomas Soderstrom already took a look at five mainstream Core i5 ATX motherbords in October, and he followed up in November with eight premium products. Now it’s time to look at reasonably-priced microATX motherboards designed to accommodate that LGA 1156 interface and discrete graphics solutions.

MicroATX

The microATX form factor is today's standard for all types of PCs that need to be small, cheap, or both. Qualifying as inexpensive usually matters most to office machines, student PCs, and other entry-level systems. As a result, microATX platforms have become somewhat synonymous with lower budgets and minimalistic feature sets. They typically have only a few expansion slots, fewer memory sockets, and less elaborate bundles of on-board integration. However, these are generalizations, not hard and fast rules. Many exceptions exist, including the four boards in this review.

Intel’s LGA 1156 interface was introduced last year, supporting the Core i5 and Core i7 processors in mid- to higher-end markets. All processors available through the beginning of 2010 came with four cores, but the dual-core models for this platform (code-named Clarkdale) launched at this year's CES 2010. The new Core i5 and Core i3 CPUs, manufactured at 32nm, come with an on-package 45nm graphics processor/PCIe/memory controller and require an H55, H57, or Q57 chipset to utilize the platform's integrated graphics. However, it's also possible to drop the new dual-core processors into a P55 motherboard, such as the ones we'll look at today.

Regardless of your processor and chipset choice, Intel's current mainstream platform is highly integrated and only consists of the processor and the Platform Controller Hub (PCH). Compared to three-chip core logic designs, such as the 3- and 4-series families (comprised of a processor, Memory Controller Hub [MCH], and I/O Controller Hub [ICH]), motherboard complexity drops significantly with a two-chip design, resulting in even smaller board footprints that are easier to design. Naturally, this is a boon to the value-seekers, unless you insist on a plethora of features and interfaces, which you'll find on enthusiast-class LGA 1156 motherboards.

Keep in mind that microATX is compatible with full-size ATX, meaning that you can install the smaller boards into all regular ATX cases. Let’s look at what the microATX segment of the P55 market has in store.

Intel P55 Express Chipset

With the introduction of its Nehalem architecture, Intel finally made a move that AMD had realized was a good idea back in 2003: integrating the memory controller into the processor. This performance-enhancing decision applies to the LGA 1366-based enthusiast platform as, well as the Lynnfield-based LGA 1156 ecosystem (but not as much to the new Clarkdale chips, which include on-package, but not on-die memory controllers). While the enthusiast platform utilizes three channels of DDR3 memory, mainstream P55 runs on dual-channel DDR3. This isn’t a real disadvantage, as our Core i7/i5 efficiency shootout revealed.

The PCI Express interface now is part of the processor, rather than situated on the chipset. Core i5/i7 CPUs for LGA 1156 (and centering on the quad-core Lynnfield design) allow either one x16 PCI Express 2.0 connection or two x8 connections for dual graphics setups. Core i3/i5 CPUs based on Clarkdale don't let you divide up the PCIe connectivity at all, unfortunately.

None of the reviewed boards actually makes use of the switches needed to achieve a x8/x8 configuration, but all except Foxconn still offer two physical x16 slots. The secondary slots are driven by four 2.5 GT/s lanes from the PCH, which we've shown is not ideal for dual-card configurations. Foxconn also makes the equivalent four lanes available through a x4 PCIe slot, more correctly conveying its usefulness paired to high-end storage and network controllers.

As mentioned, all PCIe lanes exceeding the Core i5 processor’s 16 have to be derived from the P55 chipset (unless you're looking at a board with Nvidia's nForce 200 bridge chip, which can multiplex the CPU's connectivity into 32 lanes). P55 itself serves up a total of eight lanes. Intel calls them PCI Express 2.0-compliant, but they only run at half-speed, achieving bandwidth comparable to previous-generation PCIe links. Consequently, we advise against running serious dual graphics setups on these microATX boards.

The P55 PCH also offers 14 USB 2.0 ports, an HD Audio controller, and six SATA/300 ports with AHCI and Native Command Queuing, as well as RAID support (through Intel’s Matrix Storage Technology). All of this can be considered pretty much standard across any P55-based platform.