I ran about 100 performance benchmarks on this new cluster compute instance and published results on our blog. It uses Nehalem X5570 with 16 hyper-threaded cores (8 physical), HVM, and 10 Gbps non-blocking network for the EBS volume. Out of 134 different virtual and bare-metal cloud servers I've benchmarked from EC2, Linode, Rackspace and other vendors, the EC2 cluster instance is the fastest in almost every category (CPU, disk IO, encoding, database, others).<p><a href="http://cloudharmony.com/b/2010/09/benchmarking-of-ec2s-new-cluster.html" rel="nofollow">http://cloudharmony.com/b/2010/09/benchmarking-of-ec2s-new-c...</a>