I was going through setting up the event store on some amazon nodes for a blog post http://geteventstore.com/blog/?p=49
I worked with a HIGH IO node which is stated to be
High I/O Quadruple Extra Large 60.5 GB memory, 35 EC2 Compute Units, 2 * 1024 GB of SSD-based local instance storage, 64-bit platform, 10 Gigabit Ethernet
In performance benchmarks it came out roughly the same as my zenbook ux21 laptop. Write latency was actually 20ms higher. Given it has 2TB of storage at that latency where as my laptop has 128mb but don’t forget that machines in the cloud are not really equivalent to physical hardware machines!