A look at Asus’ P7P55D and Gigabyte’s GA-P55-UD4P motherboards

Intel’s Lynnfield-based Core i5 and i7 processors arrived in style last week, boasting phenomenal performance, frugal power consumption, and affordable prices starting at just $200. Ostensibly targeted at “mainstream” audiences, these first examples of Nehalem trickle-down have many of us pondering system upgrades. Lynnfield CPUs won’t drop into existing LGA1366 or LGA775 sockets, though, so upgraders will have to seek out new motherboards with 1156-pin Land Grid Arrays and Intel’s latest P55 Express chipset.

We looked at a trio of P55 mobos from The Big Three in our chipset launch coverage, but we were unable to come up with a solid recommendation because the Asus and Gigabyte entries carried suggested retail prices of $229 and $250, respectively. That’s a heck of a lot to pay for a mid-range processor platform at a time when motherboards have next to no real impact on application or gaming performance. The only upgrades you seem to get over more vanilla models are gimmicky extras that are rarely truly useful, extra SATA and GigE ports that few actually need, and the spoils of a power-phase pissing match between manufacturers, which I suspect may only benefit the most hardcore of liquid-nitrogen-fueled extreme overclockers.

But really, it’s the exceptional quality of more affordable mid-range motherboards that makes higher-end variants look a little ostentatious. I’ve been testing two examples of the breed in Asus’ P7P55D and Gigabyte’s GA-P55-UD4P. Each has much to offer, but with a few quirks and caveats attached. Keep reading to see if either might be right for the Lynnfield system you’ve been piecing together in your head.

Asus’ P7P55D motherboard
Subtract Deluxe, er, ness

We’ve already covered the P7P55D’s Deluxe cousin, which is currently selling for over $220 online. This standard model costs $70 less at just $150, so you save a lot. The real question is, what do you lose?

A few board layers, for starters. The Deluxe’s PCB stacks eight layers and an en vogue two ounces of copper, while the standard model must make do with four floors and one ounce of the conductive stuff. Those differences shouldn’t matter when running at stock speeds, but we’ll have to see whether it affects the P7P55D’s overclocking potential. At least Asus has used fancy electrical components and solid-state capacitors throughout this vanilla model.

Asus also gives you all the essentials in terms of peripherals and connectivity, but little more. The relative lack of auxiliary chips, ports, and other extraneous hardware makes for a clean layout that beautifully illustrates the simple elegance of Intel’s Lynnfield/PCH tag team. The fact that the layout feels this spacious even with a dramatically oversized PCH heatsink is even more impressive. Not having a north bridge chip really does free up a lot of real estate.

There’s an abstractness to the P7P55D’s heatsinks that gives the board a little more aesthetic flair than one might otherwise expect from a basic model. The layers of blue are nicely understated, but they pop nicely off the dark backdrop.

14 power phases ring the P7P55D’s CPU socket, five fewer than on the Deluxe. 12 of those phases are dedicated to the processor core with the remaining two assigned to the CPU’s uncore elements. Of course, you won’t need that many power phases active at all times. The board can dynamically scale the number of power phases it’s using based on the system load. Asus also employs a microcontroller to monitor power-phase temperatures and balance the load accordingly, ideally resulting in more stable voltage delivery and lower system temperatures.

There’s plenty of clearance around the P7P55D’s socket, and the funky single-tab DIMM slots allow memory modules to be removed even with longer graphics cards installed. These slots don’t hold memory sticks quite as securely as standard ones, though. If you’re trunking your system to a LAN party, you might want to check to make sure your RAM is seated properly before powering things up.

Asus bucks the trend toward edge-mounted SATA ports by mounting the P7P55D’s face up on the board. This makes for easier cable routing in extremely tight cases that put the hard drive cage right next to the motherboard tray. However, it also has some clearance consequences. Longer, double-wide graphics cards installed in the secondary x16 slot can compromise access to two Serial ATA ports. Of course, that still leaves you with five connected to the P55 PCH.

Longer graphics cards should have no problem extending over the board’s low-profile chipset cooler. What the heatsink lacks in height it more than makes up for in sheer area. The cooler is mostly for show, though; the chipset’s TDP rating is just 4.7W, so it hardly requires aggressive cooling.

Without a north bridge to worry about, the P7P55D easily accommodates seven expansion slots, including a pair of PCIe x16 slots. The top slot gets a full 16 lanes of PCIe 2.0 from the CPU, while the second slot harnesses four of the not-quite-second-gen PCI Express lanes built into the PCH. Intel labels the P55’s eight PCI Express lanes as 2.0, but they only signal at 2.5GT/s—gen-one speed. That’s still plenty of bandwidth for Gigabit Ethernet and most reasonable auxiliary storage configurations. However, it might be a hindrance to CrossFire configurations.

Nvidia won’t endorse even full-bandwidth x16/x4 configurations for SLI, so this full-bandwidth x16, half-bandwidth x4 setup definitely isn’t fit for certification. However, the company stamps such slot configs on P55 boards with the “PhysX Ready” label, which means you can dedicate one GeForce to graphics and have another one in the lower-bandwidth slot taking care of PhysX computations.

The P7P55D’s port cluster is perhaps best described as complete. All the usual bases have been covered, including digital audio output, FireWire, and eSATA. Unfortunately, the eSATA port isn’t of the USB-powered hybrid variety we’ve seen on some other P55 mobos. I’m also not crazy about the Via VT1828S audio codec sitting behind the board’s array of audio jacks. Sure, it supports Blu-ray playback, but it can’t encode multi-channel digital audio on the fly, forcing surround-sound gamers to use the board’s analog audio outputs.

As far as I can tell, the vanilla P7P55D’s BIOS is just as well-equipped for tweaking and overclocking as that of its Deluxe counterpart. Both offer ample ranges and granularity for clock speed and voltage controls, a wealth of memory timing options, integrated flashing utilities, support for multiple configuration profiles, and a well-organized, easy-to-use interface that Asus has been carefully massaging for years.

Considering how long it’s been developing motherboard BIOSes, you’d think Asus would have a few more tricks up its sleeve on the fan control front. Apparently not. The CPU and system fan headers can be toggled between three pre-defined fan speed profiles, but that’s about it. I’d like to see options that define minimum fan speeds and target temperatures in addition to some control over how aggressively fan voltages increase in response to rising temperatures. Asus is apparently working to bring better fan speed controls to its motherboard BIOSes, and we saw a hint of their efforts with the 785G-based M4A785TD-V EVO. No such luck with Asus’ current crop of P55 offerings, though.

Gigabyte’s GA-P55-UD4P motherboard
Sensibly stacked

With a street price hovering around $250, the Gigabyte GA-P55-UD6 we looked at during our P55 launch coverage is decidedly not a mid-range motherboard. The $170 GA-P55-UD4P is certainly more reasonably priced, even if it does run $20 more than Asus’ P7P55D. Fortunately, the extra $20 hasn’t been frittered away on gaudy lighting effects, questionable accessories, or other wasteful avenues. Instead, Gigabyte has beefed up the UD4P’s hardware, which ultimately makes for a more versatile board.

Like the P7P55D, however, the board itself isn’t quite as fancy as more indulgent models. There are only four board layers, down from eight on the UD6. Gigabyte still squeezes in two-ounce copper layers, though. It also litters the board with high-quality electrical components, such as ferrite-core chokes, low RDS(on) MOSFETs, and solid-state capacitors.

Just looking at the UD4P, you might think the board had traditional north and south bridge chipset components. The P55 PCH is actually in the lower right-hand corner, as we just saw with the P7P55D. What looks like a north bridge cooler is acting as an additional heatsink for the board’s power regulation circuitry. This extra chunk of aluminum crowds the layout a little, and it could conflict with larger aftermarket heatsinks that fan out from the socket. So could the DIMM slots, which are quite close to the socket.

Gigabyte has a good thing going with its new toned-down approach to color palettes. The trademark turquoisey blue board works well with the white and light blue accents and darker heatsinks. However, none of the four sets of “racing stripes” actually match, let alone point in a consistent direction. A couple of white stripes down the middle of the board would look much racier, I think.

The UD4P has eight power phases running to the processor, which is fewer than the less expensive Asus board. I wouldn’t spend too much time counting phases, though. MSI’s mid-range P55-GD65 is a six-phase design, yet it easily overclocked to a 200MHz base clock speed and auto-piloted a Core i5-750 to 3.34GHz on just 1.352V. One doesn’t necessarily need loads of power phases, even when engaged in spirited overclocking.

Since you won’t need all eight phases while idling or even performing basic tasks, the Gigabyte board dynamically scales the number in use. However, unlike the P7P55D, there’s no apparent provision to juggle lower loads between different phase blocks.

Edge-mounted SATA connectors make an appearance on the UD4P. They’re set back a little, too, which provides just a smidgen of extra clearance for hard drive cages that might be in close proximity in smaller enclosures. At least none of the eight ports will be obscured by longer graphics cards. The low-profile PCH cooler shouldn’t be a problem, either.

Gigabyte manages to squeeze in seven expansion slots, but the top x1 is of dubious value. Right behind it sits the board’s hood ornament auxiliary power circuitry heatsink, limiting compatibility with longer cards. Shorter ones, too: my stubby PCIe x1 Gigabit Ethernet card won’t even fit into the slot.

The UD4P’s pair of PCIe x16 slots is far more promising. Both stem from the Lynnfield CPU, which means you get either a full 16 lanes of bandwidth to one slot or eight lanes to each of them. CrossFire support is a given, of course, and this board is also SLI-certified.

One could easily be forgiven for mistaking the UD4P’s port cluster for one from an extravagant, high-end unit. The spread is deliciously packed with goodness, including pairs of S/PDIF outputs, FireWire connectors, GigE jacks, and eSATA ports. Those external Serial ATA ports don’t have built-in USB power, which is a shame, but the port cluster does have a whopping ten standard USB ports.

I’m not a huge fan of integrated motherboard audio, but I have to give Gigabyte props for using Realtek’s ALC889A codec. It’s the only codec that can do on-the-fly Dolby Digital Live encoding, which is great for anyone with a compatible receiver or speakers. We’ll see how the ALC889A and UD4P fare when we measure analog audio signal quality in a moment.

Although they use very different interfaces and even different color schemes, the Asus and Gigabyte BIOSes we’ve seen on this first batch of P55 motherboards have been nearly equivalent in terms of their overclocking and tweaking options, overall feature sets, and general usability. You can tease out little differences here and there, such as Gigabyte’s nifty settings summary screen and its support for per-channel memory timings, but it’s really hard to find fault with either’s approach. That is until we get to automatic fan speed control, which amounts to an on/off switch for only the UD4P’s processor fan. I know I gripe about this a lot, but it’s ridiculous; a BIOS that offers millivolt granularity for a whopping eight different system voltages shouldn’t be saddled with stone-age fan speed controls.

At least Gigabyte has BIOS backups covered. The UD4P’s secondary BIOS chip can be a real life-saver should you corrupt the original with a bad flash or some other disaster.

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.

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.

We’ve tested the Asus and Gigabyte boards against each other and a handful of others based on the P55 chipset. Keep an eye on MSI’s P55-GD65, which sits right between the P7P55D and GA-P55-UD4P on the price ladder.

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.

Make that minuscule differences, at least for memory bandwidth. We see virtually no difference in Stream rates between all five Lynnfield motherboards. Scores in CPU-Z’s latency test are pretty tight, too, with less than a nanosecond separating the P55 pack. That’s what you get with a common CPU, memory speed, and timings. No wonder application and game performance doesn’t vary much from one motherboard to the next.

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 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.

When idling, none can match MSI’s P55-GD65 with its power-saving voodoo enabled. The fact that you don’t have to fuss with Windows software to get the lowest power draw of the lot is a nice bonus, too. The UD4P draws about four more watts depending on whether DES is running; the software actually raised power consumption slightly at idle.

Trailing the UD4P by nearly 10 watts, we find the P7P55D, which consumes even more power in XtremePhase mode. But what about under load?

The UD4P’s DES mode really shines under load, sucking eight fewer watts than the GD65 that leads the rest of the field. Asus fares better here, but mostly because the meat of the field is much more tightly packed.

We tested with Asus’ EPU software in auto mode, but there’s also a medium setting that results in a slightly higher 102W idle power consumption while pulling just 221W under load. Those numbers still lie behind the Gigabyte board’s, but they represent a notable improvement.

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

Despite using the very same FireWire silicon as its Deluxe brethren, the P7P55D’s FireWire performance isn’t up to par. The MSI board also uses a Via chip, but it’s a different model, and obviously not a faster one.

Most of the P55 boards are locked in a dead heat here, but the MSI is a little slower than its Asus and Gigabyte counterparts.

You’re better off using P55-bound Serial ATA ports over ones tied to JMicron or GSATA (otherwise known as Silicon Image) controllers. Interestingly, though, the Gigabyte and MSI boards have lower P55 burst speeds than the Asus models.

The P7P55D and UD4P both have solid Gigabyte Ethernet implementations, the Gigabyte board just has two of ’em. So does the GD65, which offers similar throughput and CPU utilization.

All hail the crab, king of audio codecs. The Gigabyte and MSI boards all use Realtek codec chips, and they score better in RightMark’s signal quality tests than the Asus models, which tap Via codecs. Of course, you’re better off with a discrete sound card if you’re really picky about analog audio quality.

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 P7P55D cruised up to 210MHz without so much as a whimper, but it hit the wall at 220MHz. Not even reasonably aggressive voltage tweaking would coax the board to post at 220MHz, let alone boot into Windows. 210MHz is still quite impressive considering that we started at 133, though.

We had much the same luck with the UD4P, which also stalled at 220MHz after effortlessly sauntering up to 210MHz. Again, we tried applying extra voltages all around, to no avail. Relaxing memory timings and fiddling with QPI link speeds didn’t help, either.

Next, we turned over control to the motherboards to see how far they might like to push our Core i5-750 CPU. Gigabyte handles auto-overclocking with its Smart QuickBoost software, which chooses an appropriate clock speed based on data the company has gathered when overclocking samples of the same CPU. The most aggressive Twin Turbo mode selected a base clock speed of 160MHz, good for 3.2GHz for the processor core.

Or 3.36GHz with Turbo Boost in action, as it is here. The board was perfectly stable at this speed, and according to CPU-Z, the processor required only 1.2V. That’s not bad for auto-pilot.

Asus has a much more iterative approach to automatic overclocking that actually steps through different clock speeds and tests for stability. This feature can be invoked through the BIOS or optional Windows software, and Asus has updated both since our look at the P7P55D Deluxe last week.

The latest BIOS’s auto-overclocking tool works much better than the earlier iteration we used. It settled on a 159MHz base clock, good for 3.35GHz at 1.328V.

Asus’ TurboV Windows software was arguably more effective, honing in on a 157MHz base clock that resulted in a slightly slower 3.3GHz core, but on only 1.256V. Both configurations were stable under load.

In theory, I prefer Asus’ iterative approach to automatic overclocking. There’s something to be said for automating the trial and error that one usually has to endure when testing a new system’s limits. However, it’s still a time-consuming project that lasted long enough that I just walked away after a while. Gigabyte’s software took a single click and reboot, and it ended up with the highest clock speed (just barely) and the lowest core voltage, all without sacrificing stability.

Seasoned PC enthusiasts are likely to use these auto-overclocking schemes to establish a launch point for further, hands-on fine tuning. Gigabyte’s software looks like it might be the best option for that sort of task, if only because it’s much quicker than waiting for the Asus board to do its thing.