Not bad, but a today athlon x2 with ddr2 800 runs more than 2200 MB/s, and a core2 with ddr2 800 runs more than 4000 MB/s.
athlons 64 do a lot more than 2200 MB/s.
How are you measuring this? The sam board doesn't look too bad to me.
On my 1583MHz Sempron w/ DDR333:
REP MOVSD (mem copy) = 330MB/S
REP LODSD (mem read) = 650MB/S
REP LODSD (mem read in L1 cache) = 3.0GB/S
