el problema .basicamente es que la controladora de tu placa es mala y antigua
y no saca el rendimiento del disco. en esa epoca funcionaban bien los sata 150
pero en los sata 300 ya casi no mejoraba el rendimiento
compraste un disco muy moderno para una placa anticuada y mediocre
CPU AMD Socket 939 Athlon64/Athlon64 FX/Athlon64 X2/ Processors
AMD Cool 'n' Quiet™ Technology
AMD 64 architecture enables simultaneous 32-bit and 64-bit computing
Chipset VIA K8T890
VIA VT8237R
System Bus 2000/ MT/s
Memory 4 x184-pin DIMM, Max. 4 GB, DDR 400/333/266 SDRAM ,ECC,Non-ECC,Un-buffered Memory
Dual Channel memory architecture
Expansion Slots 1 x PCIe x16
2 x PCIe x1
3 x PCI
Storage Southbridge
2 xUltraDMA 133/100/66/33
2 xSATA 3 Gb/s ports Support RAID 0,1,JBOD
Audio Realtek ALC850 8 -Channel CODEC
S/PDIF out on back I/O port
Universal Audio Jack
Audio Sensing and Enumeration Technology
LAN Marvell 88E8053 GbE Gigabit Lan PCI Controller supporting Gigabit/100/10 BASE-T Ethernet, features AI NET2 Virtual Cable Tester(VCT) Net-Diagnosing Utility
USB 8 USB 2.0 ports
ASUS AI Proactive Features Precision Tweaker
PEG (PCI Express Graphics) Link Mode
AI NET2 network diagnosis before entering OS
Overclocking Features Intelligent overclocking tools
ASUS PEG Link
AI Overclocking (intelligent CPU frequency tuner)
Precision Tweaker
Offers ways to raise system performance inch-by-inch and step-by-step to achieve maximum performance.
CPU, Memory, and PCIe x16 voltage adjustable
SFS (Stepless Frequency Selection)
FSB tuning from 200MHz up to 400MHz at 1MHz increment
Adjustable FSB/DDR ratio. Fixed PCI/PCIe frequencies
Overclocking Protection
ASUS C.P.R.(CPU Parameter Recall)
Special Features ASUS MyLogo 2
ASUS CrashFree BIOS 2
ASUS Q-Fan
Back Panel I/O Ports 1 x Parallel
1 x PS/2 Keyboard
1 x PS/2 Mouse
1 x S/PDIF Out
1 x LAN(RJ45) port
4 x USB 2.0/1.1
8 -Channel Audio I/O
Internal I/O Connectors 2 x USB connectors supports additional 4 USB 2.0 ports
1 x CPU Fan connector
1 x Chassis Fan connector
1 x Power Fan connector
1 x4-pin ATX 12V Power connector
24 -pin ATX Power connector
Front panel audio connector
COM connector
Chassis Intrusion connector
CD/AUX audio in
BIOS 4 Mb Flash ROM
DMI 2.0
PnP
WfM 2.0
SM BIOS 2.3
Award BIOS
Manageability WfM 2.0,DMI 2.0,WOL by PME,WOR by PME,Chasis Intrusion,
Support Disc Drivers
ASUS PC Probe
Anti-virus software (OEM version)
ASUS LiveUpdate Utility
Accessories User's manual
x IDE cables
x UltraDMA 133/100/66 cables
x Floppy disk drive cables
x SATA cables
SATA power cables
I/O Shield
Form Factor ATX Form Factor
12 inch x 9.6 inch ( 30.5 cm x 24.5 cm )
Prueba en VIA a buscar controladores para el chipset y actualiza la bios
comprueba tu version de BIOS la ultima es la 1010 :http://www.asus.com/product.aspx?P_ID=VMfiJJRYTHM4gXIi&templete=2
saludos