We have seen a number of leaked WP8 devices show up on the WP Bench benchmarking site, but so far none have submitted benchmark scores.
The mysterious Juggernaut Alpha seems to have been the first, scoring a massive 151.14, about 50% more than the best other device, the HTC Titan.
The device is likely has dual-core Snapdragon processor, and the performance increase is what one can expect for Windows Phone 7 apps running on Windows Phone 8. Windows Phone 8 apps themselves will be able to take advantage of native code, and will be many times faster at completing processor-intensive tasks than Windows Phone 7 handsets.
Given that Windows Phones already have a reputation for being smooth and fast, is this a reason to upgrade to a new Windows Phone 8 handset?
WP Bench can be found in Marketplace here.