While Amazon EC2 uses Xen virtualization, our KVM multi-core benchmarks from last week show Apache not scaling too well in virtualized environments so it's not too much of a surprise that Amazon m1.large and m1.xlarge were well behind even the AMD Opteron 2384 workstation.
The Amazon EC2 instances were comparable to the SSD-backed Opteron workstation in the SQLite benchmark while the HDD Core i7 970 system was well behind.
It is similar for the PostMark results too.
When it comes to the Bullet Physics Engine, the Amazon EC2 m1.xlarge was comparable to that of the Opteron 2394 while the Core i7 970 12-logical-thread system was about twice as fast. The m1.large EC2 instance lagged behind.