We already knew that Froyo (Android 2.2) offered some awesome performance improvements. How does it compare against the iPhone 4, Apple's lefty-hating smartphone? It blows it away.

Ars did a recent review of Froyo, and now has taken the time to compare the iPhone 4 with the Nexus One running Froyo in terms of two JavaScript benchmarks, SunSpider and V8.

As you can see above, in SunSpider (lower is better), Froyo scored 5,795.2 vs. 10,902.1, close to a 2 to 1 difference.. In V8 (higher is better), Froyo scored 287 vs. 67, a more than 4 to 1 advantage.

Granted, this tests are focused on JavaScript, and are synthetic tests to boot. What matters to most people is that both phones are capable devices (except, in the case of an iPhone 4, if you want to make a call using your left hand and no case). It also uses top of the line hardware on the Android side, the Nexus One (which is the only Android device to get Froyo so far, so there wasn't really a choice).

However, while the Nexus One running Froyo is pretty much still top of the line hardware, once the Samsung Galaxy S devices hit, with their Hummingbird CPU, might we see a still bigger difference between the two?

The phone wars will continue to be very interesting, especially with Android devices getting new hardware all the time, while the iPhone will wait a year for a refresh (except, perhaps, for a Verizon iPhone?).