Hi Kongji,
Lenovo x61 bios is limited to SATA 1.5gbps although the chipset supports SATA 3.0gbps
You might want to flash to the hacked bios which enables SATA 3.0gbps
http://forum.notebookreview.com/6501443-post75.html
I used the hacked bios to enable SATA 3.0gbps with T61 & Kingston V+100, and it works pretty well.
If this bios helps, my guess is that maybe the Sandisk Extreme doesn’t work well on SATA 1.5gbps on older hardware?
