Google is a strange beast when it comes to betas. Gmail has reams of functionality and sits in beta virtually 5 years (to the day) since release. Chrome on the other hand doesn't yet support RRS feeds but we're already onto v2.0...
Version '188.8.131.52' is the first public beta of the second generation of Chrome and it focuses on perhaps the one area it doesn't really need to: performance.
Google is claiming speed improvements of up to 25 per cent and 35 per cent on the V8 and Sunspider benchmarks respectively from latest 1.x edition and virtually double the speed of the original Chrome beta. On top of this 184.108.40.206 scores a 100 per cent pass rate on Acid3.
In terms of features the gains are sadly less significant however with basic functionality such as form autofill, full page zoom and autoscroll now supported. A Windows 7-esque ability to drag tabs into a side by side view is also in there. As for Chrome extensions, no sign yet.
The new Chrome beta officially runs on Vista and XP SP2+ but I've found it also works just fine on Windows 7 - as do most things. Grab it from the link below.