scp only uses compression if you tell it to ('-C' flag). and both ftp and scp involve disk access as part of the test.
If you just want to test your nics, use one of the tools above, like netperf (very simple). It only uses memory (fast), system buses (also fast) and and network hardware. If you get good results, it might be a good next step to try ftp or some file-based test to see if file i/o is the point of slowness.