Sony has released a firmware update for the PlayStation Portable (PSP) which finally allows the much-touted interconnectivity between the handheld device and the PlayStation 3.

However, it has emerged that the gaming giant may have slipped a little unannounced bonus into the package.

A number of gaming sites are reporting that Sony has included a CPU clock upgrade in the version 3.50 firmware upgrade currently only available to North American users.

The clock upgrade will increase the down-clocked 266MHz CPU back to the full pre-release 333MHz.

Fans of the device made much noise when the PSP was released about the downgrading of the CPU's front side bus speed. However, it is rumoured that Sony made the sacrifice in order to improve the battery life of the device.

Current speculation suggests that Sony has decided to increase the clock speed of the unit to better go up against Nintendo's DS, but it is also rumoured that a redesigned version of the gaming console may be on the cards.

At any rate, an increased clock speed should pave the way for a new batch of more hardware-demanding games.

On Sony's official US website, the only confirmed upgrades in the version 3.50 firmware update are new communications settings and an RSS feed channel, and the Remote Play functionality enabling the device to connect to a PS3 over the internet.