The memory performance is almost identical, which is understandable considering the CPU controls the memory access not the motherboard, however a poorly designed motherboard will add extra latency and lower overall bandwidth.
Drive Performance:
We used a 74GB Western Digital Raptor hard drive for our SATA performance testing, while a 500GB Seagate eSATA drive was used for eSATA performance testing. We recorded the average read speeds in all cases using HD Tach 3.0.1.0's 8MB zone test.
SATA Hard Drive Performance
HDTach 3.0.1.0, 8MB Zone Test, Average Read
Gigabyte MA790FX-DQ6
Asus M2N32-SLI Deluxe
64.3
64.3
0
10
20
30
40
50
60
70
MB/s
eSATA Performance
HDTach 3.0.1.0, 8MB Zone Test, Average Read
Gigabyte MA790FX-DQ6
Asus M2N32-SLI Deluxe
51.0
51.0
0
10
20
30
40
50
MB/s
The drive scores are identical, which means both boards SATA and eSATA performance is consistent and very good.