It has been reported than the latest Surface Pro 2 tablets are shipping with a new CPU.

The upgrade is to a 1.9GHz Core i5 4300 from an Intel 1.6GHz Core i5 4200U processor, which was shipped with the device in its October release.

"I returned my Surface Pro 2 (v. 256GB) because of the poor performance after the failed 12.10.13 firmware update. I recall the SP2 I returned having a i5 4200U processor. To my surprise, when I checked the System Properties in the Control Panel on my replacement SP2, the processor was upgraded to a i5 4300U @ 1.9Ghz. – 2.5 Ghz," a Surface Pro 2 owner stated on Microsoft’s official support forum.

Microsoft confirmed that small changes to internal components do take place over the lifetime of the product.

Many users were left angered by December’s firmware update, which saw many Surface Pro 2s returned.

Microsoft has yet to roll out the updated firmware update, which promises improved system stability, an updated WiFi driver, improved Surface Cover interaction, an optimized two-finger trackpad, and improved colour for applications.