Technically speaking, the Acer Aspire M5-581T-6405 is an ultrabook, albeit a rather large one. It uses a low-powered Ivy Bridge Core i5 processor, has a solid-state drive, and is 0.8-inch thick. However, it has a 15.6-inch screen, a rarity among ultrabooks. Performance-wise, it holds its own against similarly configured ultrabooks, and its price is downright reasonable, considering it has a backlit keyboard and a metallic chassis. That said, its lack of touch-screen technology holds it back.

Design and Features
The M5-581T-6405 looks exactly like the Acer Aspire M5-481PT-6644, only bigger. Both sport a brushed metal chassis and both have the requisite Acer logo emblazoned on the lid, which is held in place by a pair of strong, durable hinges. The M5-581T measures 14.4-by-10.1-by-0.8 inches (WDH) and weighs 5 pounds, making it one of the bulkier ultrabooks around, especially when compared to models such at the Toshiba Portege Z935-P300 and the Acer Aspire S7-391-9886. Still, it's not a backbreaker and is certainly thin enough to slide into a crowed backpack. The metal chassis stays cool and has a nice sturdy feel.

The full sized chiclet-style keyboard offers plenty of room for comfortable typing, and the keys are well spaced. The dedicated number pad is a plus, but those keys are a bit skinny. As with the Acer M5-481PT-6644, the keyboard deck is metal-clad and the entire keyboard is backlit. The one-piece touchpad is wide, offering plenty of room for pinching, zooming, swiping in Charms, and other Windows 8 gestures.

The M5-581T has a 15.6-inch display that maxes out at 1,366-by-768, a relatively low resolution for a screen of this size. Although it can't display HD content in 1080p it does do a good job of displaying 720p video and delivers a bright picture with vibrant color reproduction. Alas, the screen is not touch-enabled, so you'll have to navigate Windows 8 via the touchpad and keyboard.

Port selection is standard ultrabook issue. There are two USB 3.0 ports and one USB 2.0 port on the back of the M5 along with a LAN jack and an HDMI port. You don't get a VGA (analog) port on this model, though. The left side is home to a tray loading DVD multi-drive and the right side holds an SD/MMC card reader slot and a headphone jack. A webcam and microphone are built in to the display's upper bezel and there are two small Dolby powered speakers embedded in the base that are loud and relatively full sounding, although they could use more bottom. In addition to the gigabit LAN port the M5-581T has 802.11b/g/n and Bluetooth 4.0 networking capabilities.

The M5-581T is outfitted with a 20GB solid-state drive and a 500GB, 5,400rpm hard drive. In addition to Windows 8, you get Acer Cloud, webcam, and backup utilities, Skype, and a handful of trial (bloatware) apps such as ebay, Amazon, HuluPlus, Netflix, and MS Office. Acer covers the M5-581T with a one-year warranty.

Performance
A 1.8GHz Core i5-3337U processor and 6GB of system RAM give the M5-581T plenty of productivity power. Its PCMark 7 score of 3,241eclipsed that of the Asus VivoBook S400CA-UH51 (3013) but trailed the Acer M5-481PT-6644 (4,016), the Vizio 14-inch Thin + Light (C14-A4) (4819), and the Asus Zenbook Prime Touch UX31A-BHI5T (4510).

However, it outscored all of the above-mentioned ultrabooks on our Cinebench R11.5 CPU test, if only by a hair. It also turned in the quickest Handbrake encoding time (1 minute and 25 seconds) but needed 7 minutes and 13 seconds to complete the Photoshop CS6 workload. That's the slowest time of the bunch, with the exception of the Acer M5-481PT-6644 (7:18).

When it comes to playing video and running low- to mid-range games the M5-581T's Intel HD Graphics 4000 solution will get the job done, but it lacks the horsepower to run complex graphics-intensive games that require at least 30 fps (frames per second) to play smoothly. It managed only 11 fps on our medium quality Aliens vs. Predator test and just 7 fps on the high-quality setting. That's pretty much in line with other ultrabooks that use the integrated Intel GPU. Results were similar on our Heaven benchmark test where the M5 turned out 12 fps (medium quality) and 6 fps (high quality).

The M5-581T gave us 6 hours and 17 minutes of juice on our Battery Rundown test, which is outstanding considering it uses a 15.6-inch display. It outlasted the Acer M5-481PT-6644 (6:04), the Asus Vivobook (4:18), and the Vizio 14-inch Thin + Light (4:30) but couldn't quite keep up with the Acer Iconia W700-6465 (6:34).

With its sleek, sturdy chassis, Core i5 power, and affordable price tag, the Acer Aspire M5-581T-6405 is a good choice for users looking to enter the Windows 8 ultrabook arena without spending a fortune. Granted, it's larger than most of its competitors, but it's still very portable and you get a bright 15.6-inch screen in return. Touch-screen technology would make this a Windows 8 ultrabook to be reckoned with, however. If you have some wiggle room in your budget, consider the Acer Aspire M5-481PT-6644, our Editors' Choice for entry level touch-screen ultrabooks. It offers ten-point touch display technology, solid performance, and a 14-inch all-metal chassis for around $130 more.

BENCHMARK TEST RESULTS:
Check out the test scores for the Acer Aspire M5-581T-6405