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The dv4t's single fan has an exhaust vent on the left side of the chassis. The cooling solution kept the chassis cool even while we were running benchmark tests. The fan appears to be overreactive - it is always on even in battery mode. Ideally the fan should turn off when not needed. I wouldn't say anything except the fan does make noise and is audible in a quiet room. The fan does not develop any sort of whine or excessive noise; the fact that it's always on is kind of annoying though. Given the lack of heat the internal components produce, there's little reason for it to be on all the time.
We measured an excellent six hours, 30 minutes of battery like Hp EV087AA battery , Hp EX942AA battery , Hp Pavilion ZT3000 battery , Hp 337607-001 battery , Hp 337607-003 battery , Hp 396008-001 battery , Hp 398876-001 battery , Hp PB992A battery , Hp PB994A battery , Hp PB991A battery life during our standard battery rundown test (Windows 7 Balanced power profile, 70% screen brightness, wireless active and refreshing a web page every 60 seconds). This is a very respectable time for a budget notebook. Intel's latest Core i-series processors are very power efficient as is the included 5400RPM hard drive.
The HP Pavilion dv4t is an impressive value under $500. Its highlights include over six hours of battery life, a good keyboard and good performance for most tasks. The downsides are an overuse of glossy plastic, a fan that doesn't turn off, loud touchpad buttons and poor speakers. It all boils down to the fact that there's nothing majorly wrong with the dv4t. This notebook is ideal for home users and students looking for a basic everyday computer.