The T5120 will be good for native testing, and package compiling, that said I wouldn’t call it powerful… I have a T2000 which is nearly the same machine (same T2 CPU), and always prefer to work on my Ultra45 even though it only has 2 cores they are much faster for interactive use then the T2 which also has anemic FPU performance as well. The T2 is a throughput machine… great server / bad desktop. I’ve been eyeing getting a T4 myself since they are cheaper now to replace my T2000. The T4 has good FPU and single thread performance also.
Note you have to go up to a T4 at least to get out of order execution as well as dual issue… all the previous ones are in order and achieve high IPC by using/abusing mutlithreading. A T4 is probably 10x faster for single thread workloads than a T1 or T2. And probably over 2x as fast as a T3 most of the time.