As we've seen from previous Intel CULV laptops, the ultra-low voltage processors generally offer very decent performance for the price - certainly good enough for general computing tasks and a far cry from netbooks. This is doubly the case (literally) with the dual-core iterations, since the single-cores ones - as seen on the Medion Akoya E3211 and Toshiba Satellite T130-11H - are really quite limited.
However, this shouldn't be a problem with the ViewBook Pro since it uses the higher-end dual-core option, the SU7300, which adds 3MB L2 Cache to the 1.3GHz core-clock speed. Subjectively it performs fine, but due to the relatively (in modern terms) small amount of RAM and lack of a 64-bit OS, it's actually comfortably beaten by both the Acer Aspire 1810TZ and the HP Pavilion dm3-1020ea in our PCMark Vantage benchmarks. We wouldn't say this difference is totally representative of what you'll see in real-world use, but in the strictest sense the ViewBook Pro doesn't perform as well as either.
Of course it's not a gaming machine by any stretch, as its feeble 12.5fps in the Trackmania Nations tests attests. Since the ViewBook Pro doesn't support our usual resolution for this test (1,366 x 768), it was run at its closest equivalent (1,280 x 800), which is technically slightly lower.
Finally we come to arguably the most important factor for any ultra-portable laptop: battery life. As standard the ViewBook Pro comes with a six-cell, 4,400mAh battery. Handily, the ViewBook also employs a feature you'd normally see on more expensive business laptops: the optical drive can be replaced with a secondary battery. One of these isn't provided as standard (though you do get a blanker) and as yet we've been unable to find anyone selling such batteries. However, ViewSonic has given us an SRP of £28 excluding VAT for the black and silver versions of the batteries.
As for the provided battery, in the Productivity segment of MobileMark 2007 it managed 265 minutes (four hours, 25 minutes). This is a good result, but not an outstanding one, for a low-voltage laptop. It's close to 30 minutes less than the HP Pavilion dm3 and doesn't come anywhere near to the Acer, which lasted 523 minutes - slightly less than double. It's a shame ViewSonic doesn't include the extra battery really, as it would doubtless add a great deal of value (and battery life) to the system overall. You should be able to watch most films on a single charge, though, as the ViewBook lasted close to three hours in the DVD playback test.
ViewSonic has done some interesting things with the ViewBook Pro. It's got a great screen, has a comprehensive (sometimes eclectic) feature set and offers an integrated optical drive when others don't. It's let down, however, by a slightly unrefined chassis and a poor keyboard. A little more RAM would be nice, too.