I'm looking to upgrade the stock 2.66GHz 5150's I've got in my Pro at the moment with something with a little more juice. It chokes a little in FCPX and is seriously bottlenecking the 660 when gaming. I don't really need 8 cores - and as I've now dropped my consoles for this Mac Pro, I'm looking around for processors that are going to give me the best performance per core. The 3GHz 5160's are a nice boost and they're dirt cheap (£5 each) so I'm using that as a benchmark. I've also looked at the x5355's but, in Geekbench at least, they're slower than the 5150's on a single-core level. Thanks in advance.