Gigabyte’s GA-P55M-UD4 and MSI’s P55M-GD45 motherboards compared

Just about every system I’ve built in the last decade has used a full-sized ATX motherboard. Back in the day, you pretty much had to go ATX to get a decent board with the sort of features, BIOS options, and overclocking headroom expected by savvy enthusiasts. MicroATX offerings were largely budget fare, providing little more than the bare minimum required for basic desktops. Plus, they didn’t have enough board real estate for dual CPU sockets. After embracing the creamy smoothness of SMP early on, I wasn’t about to go back to a single core.

These days, you’d be hard-pressed to find a single-core desktop processor for sale. Dual- and quad-core CPUs have become commonplace, and they’ll easily drop into the single sockets available on MicroATX motherboards. Today’s micro mobos are much improved over their ancestors, too. Some models offer the same features as enthusiast-oriented ATX boards, including loads of integrated peripherals, identical BIOS overclocking and tweaking options, and even support for CrossFire and SLI. Plus, you can get versions with LGA1156 sockets primed for Intel’s latest Lynnfield-powered Core i5 and i7 processors.

For the first time, well, ever, I’m actually contemplating a MicroATX build for my next desktop. But should you? We’ve rounded up a couple of MicroATX P55 motherboards from Gigabyte and MSI to help answer that question, and you might be surprised at what we’ve found.

Gigabyte’s GA-P55M-UD4 motherboard
Micro without compromise

Gigabyte’s stable of P55 motherboards currently houses two MicroATX models: the GA-P55M-UD2 and the GA-P55M-UD4. The former is remarkably affordable at just $110 online, but as one might expect from a budget variant, it’s not exactly stacked with the latest and greatest. You’ll need to shell out nearly $35 more for the UD4. In return, you’ll get a board that, at least on the surface, appears to be completely free of compromise. It’s almost as if Gigabyte took one of its enthusiast-oriented ATX boards and chopped a couple of inches off the bottom.

The UD4 even looks the part, with the same turquoise, blue, and white color scheme as the rest of Gigabyte’s recent motherboards. I like the simple palette, particularly since it maintains the company’s trademark turquoisey-blue board color. However, the mismatched “racing stripes” on the heatsinks look a little odd, as does the single orange expansion slot. Old habits die hard, I guess.

Like other members of Gigabyte’s P55 family, the UD4 has a two-ounce copper layer and fancy electrical components, including solid-state capacitors, ferrite-core chokes, and lower RDS(on) MOSFETs. The board itself is four-layer design, just like the ATX-sized GA-P55-UD4P.

Interestingly, the UD4 actually has more power phases dedicated to the processor than its ATX cousin. Gigabyte packs 12 phases around the UD4’s socket, while just eight ring the UD4P’s LGA1156 Land Grid Array.

LGA1156 sockets have come under increasing scrutiny recently, with some suggesting that Foxconn-built units don’t make adequate pin contact with Lynnfield CPUs. The UD4’s socket is indeed made by Foxconn, as is the one on the MSI board. However, I didn’t experience any problems with either. Of course, I also didn’t engage in the sort of extreme, liquid-nitrogen-fueled overclocking that’s apparently scorching the offending sockets.

One might think that the six Serial ATA RAID ports available in the P55 Express chipset would be sufficient for a MicroATX motherboard like the UD4. Or not. Gigabyte adds a GSATA-branded JMicron storage controller that provides two more SATA ports and an IDE connector. Heck, there’s even a floppy port, if you’re stuck in the dark ages.

The edge-mounted SATA ports do a good job of avoiding clearance conflicts with longer graphics cards, but you might run into problems with tighter enclosures that leave little room around the motherboard tray. Serial ATA cables with right-angle ports might not help on that front, either. All the ones I have are oriented so that the cable would end up pointing down, toward the motherboard tray, if plugged into the UD4’s edge-mounted ports.

Gigabyte squeezes four expansion slots onto the UD4, including a pair of physical x16 slots that can be configured in a dual-x8 setup for SLI or CrossFire. The x4 slot is notched to accommodate longer cards, too, making it possible to run three PCI Express graphic cards, provided they all have single-slot coolers.

Having four expansion slots is still a little limiting when you’re looking at losing two to a double-wide graphics card, but then the UD4’s payload of integrated peripherals doesn’t need much embellishment. The board employs Realtek’s ALC889A audio codec—our current favorite for its ability to encode Dolby Digital Live bitstreams on the fly—and offers two flavors of S/PDIF output alongside the usual assortment of analog audio jacks. Gigabyte also includes a hybrid eSATA/USB port capable of powering compatible external Serial ATA devices without the need for auxiliary cables, which is all kinds of awesome.

If you’re familiar with the BIOSes on Gigabyte’s high-end motherboards, you’ll feel right at home with the UD4. The layout and tuning options are all but identical to what’s available on more exotic ATX models, offering enthusiasts plenty of tweaking and overclocking potential. However, Gigabyte continues to have some of the most barren automatic fan speed controls in the business. Users can identify whether they’re using a three- or four-pin CPU fan, but that’s about it. Such a simplistic toggle switch is a stark contrast to the overabundance of fine-grained clock speed, memory timing, and voltage controls available elsewhere in the BIOS. I’ve been harping on this issue for a while now, and have brought it up with Gigabyte on numerous occasions. Unfortunately, the company’s BIOS division seems entirely uninterested in developing more extensive fan speed options.

MSI’s P55M-GD45 motherboard
Black and blue and, er, MicroATX

Unlike Gigabyte, MSI has just one MicroATX motherboard in its P55 lineup: the P55M-GD45.
At close to $125 online, the GD45 costs about $20 less than the UD4. So what do you lose? SLI, for one. Although AMD supports CrossFire on just about every P55-based motherboard with a pair of physical x16 slots, Nvidia requires that individual models be SLI-certified. The GD45 will happily accommodate a couple of GeForce graphics cards as long as one is dedicated to PhysX processing, but you can’t team the pair to share the pixel-processing workload.

Of course, given the performance of AMD’s latest Radeons, SLI support is something most folks can probably do without. You can build a heck of a gaming system with just a single graphics card and still be confident that the latest titles will run fluidly at resolutions up to 2560×1600.

At first glance, the GD45 looks very much like the sort of board you might put inside a fancy gaming rig. The black-and-blue color scheme has a menacing edge, and I quite like the pewter tone of the chipset and voltage circuitry heatsinks.

The VRM cooler is tiny compared to what we’re used to seeing on enthusiast-oriented motherboards, but I’ve often wondered whether massive clumps of copper linked by intricate heatpipe arrays were really necessary. Granted, the GD45 has only four power phases supplying the processor—one third the number available on the Gigabyte board. MSI claims that just one of its so-called DrMOS MOSFETs is better than four “traditional” ones, although Asus and Gigabyte both argue that their boards use higher-quality MOSFETs than what would presumably be classified as “traditional” designs. Comparing CPU power implementations from different manufacturers is more complicated than counting phases, but it is worth noting that the GD45 has two fewer phases than MSI’s mid-range P55-GD65 ATX model.

In addition to purportedly higher-quality MOSFETs, the GD45 uses solid-state capacitors throughout. The board has four layers, just like the UD4, but its copper layer contains just a single ounce of the conductive stuff. One-ounce copper layers are still the industry standard. Although Asus and Gigabyte claim that two-ounce layers lower board-level impedance, we’ve yet to see that translate into tangible benefits for end users.

MSI eschews auxiliary storage controllers for the GD45’s internal SATA connectivity, instead relying on the six 3Gbps ports provided by the P55 chipset. As on the Gigabyte board, the edge-mounted ports leave plenty of clearance for longer graphics cards, but they could present problems in tighter enclosures that put hard drive cages or other obstructions right next to the motherboard tray. In fact, the GD45’s SATA ports are even closer to the edge than on the UD4.

Speaking of clearance issues, I should note that the DIMM slot tabs on both the UD4 and GD45 snug right up next to longer PCI Express graphics cards. This placement can make swapping memory modules difficult when a graphics card is installed, although that’s not the sort of thing most folks would do with any regularity. A little layout crowding is inescapable given the dimensional constraints presented by the MicroATX standard.

The GD45’s lack of SLI certification probably stems from the arrangement of electrical lanes connected to its physical x16 slots. All 16 of the PCI Express 2.0 lanes found in Lynnfield CPUs flow to the first slot, while the second must make do with four lanes of connectivity from the P55 chipset. Worse yet, the P55’s PCIe lanes only signal at 2.5 GT/s, which is the same speed as a first-generation PCI Express. Effectively, you’re looking at a x16/x2 configuration for dual graphics cards. That config doesn’t make the cut for SLI certification, and it may not be ideal for CrossFire, either.

A whopping ten USB ports adorn the GD45’s port cluster. Unfortunately, none of them are cross-bred with the board’s dual eSATA ports. I’d happily trade both non-powered eSATA ports for just one hybrid eSATA/USB connector.

Although the port cluster looks otherwise stacked, a digital S/PDIF audio output is conspicuously missing. There’s an S/PDIF header on the board, and the manual makes mention of an optional PCI back plate connector with an RCA output, but that part doesn’t seem to be included with any of the GD45s currently available at online retailers.

Realtek’s ALC889 codec handles the silicon side of the audio equation, but unlike the ALC889A on the Gigabyte board, real-time Dolby Digital Live encoding isn’t supported. This limitation should only affect gamers looking to output multi-channel audio over a digital connection, since the ALC889 is still capable of passing pre-encoded audio tracks, such as those found with movies, over S/PDIF.

Although the MSI and Gigabyte BIOSes differ a little in their presentation and the specific ranges and granularity available with various overclocking and tweaking options, enthusiasts engaged in the usual performance tuning should find them functionally equivalent. Fan speed controls are the obvious exception, and MSI deserves props for allowing users not only to set a target CPU temperature between 40 and 70°C in 5° increments, but also to choose a minimum fan speed between 0 and 87.5% in 12.5% increments. Even though temperature-based fan speed control isn’t available for the board’s two system fan headers, each can be set to run at 50, 75, or 100% of full speed.

The devil’s in the details
This wouldn’t be TR motherboard coverage without a painstakingly detailed assessment of each board’s BIOS options and specifications. These details don’t exactly lend themselves to eloquent prose, but you should be able to find what you need in the tables below. Note that BIOS variables preceded by a * can be keyed in directly rather than selected from what can sometimes be quite a long list of available values.

Our testing methods
We’ve narrowed our focus on motherboards today, and the testing conducted reflects that approach. If you’d like to see Lynnfield’s application and gaming performance against competing processor platforms, hit up our coverage of the CPU. For a closer inspection of the P55’s performance implications, we have an in-depth chipset review.

To determine whether these MicroATX boards can hang with the big boys, we’ve tested them against a collection of full-size ATX models. We’ve also thrown in an X58-based rig for reference.

Note that our X58-based system is only running its memory at 1066MHz—the fastest speed allowed by our Core i7-920 engineering sample. The platform’s third memory channel should easily make up the difference, but the results are only there for reference, anyway.

All tests were run at least three times, and their results were averaged.

Our test systems were powered by a PC Power & Cooling Silencer 750W power supply unit.

We’d like to thank Western Digital for sending Raptor WD1500ADFD hard drives for our test rigs.

We used the following versions of our test applications:

• TCD Labs HD Tach 3.01
• RightMark Audio Analyzer 6.2.3
• NTttcp
• CPU-Z 1.41 latency test
• Stream 5.8 64-bit

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Memory performance
Lynnfield’s on-die memory controller largely evens the playing field for P55 boards. However, each manufacturer has the freedom to tune the CPU’s integrated memory controller, and that can lead to small but consistent bandwidth and latency differences.

There’s very little difference in memory performance between the P55 boards, and the MicroATX models are right in the thick of things. In fact, the GD45 takes the top spot in CPU-Z’s memory latency test, albeit just barely.

Power consumption
Of course, performance is only one part of the equation for a modern PC. Power consumption counts for a lot these days, and that’s an area where motherboards can really set themselves apart. We’ve measured total system power consumption, sans monitors and speakers, at the wall outlet with a Watts Up Pro power meter. Readings were taken at idle and under a load consisting of a Cinebench render alongside the rthdribl HDR lighting demo. Windows 7’s “Balanced” performance profile, which uses CPU power management features, was enabled for this and all of our other tests.

Power consumption has become a hot topic among motherboard makers of late, and each board has a few different configuration options tied to BIOS switches and additional Windows software. MSI takes the simplest approach: either enable active power-phase switching (APS in the graphs below) or leave it off. With Gigabyte, you can run with or without Dynamic Energy Saver software installed. The Dynamic Energy Saver software didn’t work right with the UD5 BIOS revision we used for testing, though. Asus offers three options: an Xtreme Phase mode that’s enabled by default, an Xtreme-less normal operation mode, and a third mode calibrated by EPU software for Windows.

The MicroATX boards are among the most power-efficient at idle, with the GD45 drawing about a watt less than the UD4. Interestingly, the power-phase-switching capabilities of both micro models do little to lower system power consumption here.

MSI’s APS scheme doesn’t have much impact under load, either, but Gigabyte’s Dynamic Energy Saver software shaves more than 10W off the UD4’s socket draw. Having to run the DES Windows app to enjoy these power savings is a little annoying, though. The BIOS switch used to toggle APS on the MSI board is much less obtrusive.

The UD4 and GD45 both have admirably low power consumption overall. However, neither board is substantially more power-efficient than comparable ATX models.

Motherboard peripheral performance
To provide a closer look at the peripheral performance you can expect from these motherboards, we’ve compiled Ethernet, Serial ATA, USB, FireWire, and audio performance results below.

The GD45’s FireWire read speeds are quicker than those of the UD4, but write speeds are nearly identical.

Even though the MSI and Gigabyte boards use the exact same P55 USB controller, Gigabyte’s implementation is a little quicker overall, and notably faster in HD Tach’s write speed test.

Neither Gigabyte nor MSI seems to have figured out how to get the P55’s SATA burst speeds up to par. Thus far, only Asus has the VelociRaptor we use for these tests bursting at its full potential.

Thankfully, the days of PCI-based Gigabit Ethernet controllers are largely behind us. The PCIe GigE chips on the MicroATX boards deliver nearly equivalent throughput and CPU utilization.

The UD4 and GD45 score identically in a RightMark Audio Analyzer loopback test between their respective front-channel outputs and line inputs.

Overclocking
Although it’s still early days, Lynnfield appears to be a willing overclocker. You have two options with the boards we’re looking at today: kick it old-school by cranking base clock speeds or use trendy new auto-overclocking features that seem to be all the rage. We’ve tested both, and I’ll start with the retro approach.

To probe each board’s base clock speed limits, we dialed back the CPU and memory multipliers to take them out of the equation. Next, we ramped up the base clock speed, testing for stability along the way with a combined Prime95/rthdribl load.

The UD4 effortlessly cruised up to a 210MHz base clock speed without so much as a bump in voltage. 220MHz wouldn’t post, though, and tweaking processor and chipset voltages didn’t help. I even tried relaxing memory timings, but the UD4 stubbornly refused to cooperate.

Like the UD4, the GD45 reached its peak stable base clock speed without extra voltage, and upping the voltage didn’t help. The board only made it up to 200MHz, but that’s still pretty respectable, and more than enough headroom for air-cooled processor overclocking.

What’s most interesting about these results is that they don’t stray from the peak base clock speeds we’ve achieved with full-size ATX boards from Gigabyte and MSI. That’s promising news for anyone leery of overclocking with a MicroATX mobo—well, these ones, anyway.

Next, we turned our attention to the auto-overclocking schemes offered by each board, starting with the UD4. Gigabyte’s Smart QuickBoost software selects a CPU clock speed based on the company’s own experience overclocking the processor in question. With our Core i5-750, QuickBoost settled on a 160MHz base clock speed. With Turbo Boost, that took the CPU up to 3.36GHz on just 1.216V.

This is the same clock speed that QuickBoost chose for the processor when we ran it on the UD4’s ATX siblings. Our i5-750 seems to be perfectly comfortable at 3.36GHz, too, even under a demanding four-way Prime95 load.

MSI’s approach to automatic CPU overclocking revolves around an OC Genie BIOS switch. Enabling OC Genie automagically overclocks the CPU at the next reboot, and it arrived at a somewhat different conclusion than QuickBoost.

OC Genie actually lowered the system’s CPU multiplier to 17X and then cranked the Base clock speed past 190MHz, pushing the CPU to 3.27GHz. That’s a little slower than what QuickBoost achieved, and it required a smidgen more voltage—1.312V, according to CPU-Z.

While I prefer overclocking the old-fashioned way, I do appreciate the fact that OC Genie doesn’t require Windows software. Of course, if the point of an automated approach is to bring overclocking to users who would otherwise be intimidated by poking around in the BIOS, Windows software might actually be preferable.