I have 4 p.c.s with SeaGate Barracuda ST3250310AS 250 GB Hard Disks installed in them . These pc.s have 2.7GHz AMD Athalon 64 X2 CPUs & Asus M2N68-AM SE2 Mobos . There is 2 GB DDR2 RAM installed in each of these machines (not dual-channeled) . They also have XFX GeForce 8400GS Cards . However when I transferred a 1.54 GB Folder from 1 Partition to another in each of these machines , the folder was transferred @ 20 to 30 MB/s . My other machine is a Pentium D 820 2.8 GHz with 512 MB DDR RAM & 80 GB Western Digital WDC WD800BD-22LRA0 (74 GB) Hard Disk . The mobo is MS-7101 fom MicroStar . Even on this machine , when I tried copying the file from 1 Partition to another , I got a speed of about 10 MB/s . The connection protocol on all p.c.s seems to be ATA/ATAPI 7) . My Question is as follows : I recently found out from Wikipedia that Sata Hard Drives support 150 to 600 MB/s speed . Also , on the Seagate Website , the Barracuda ST3250310AS 250 GB Hard Disk is mentioned as having 3Gb/s speed (about 375 MB/s) . Then why am I not getting such speeds from my Hard Drives ?