It was not clear to me which Intel SSDs you were referring to, since your issue is with the X25-E.
A "Live system" is not used often in the US, and who knows what it's composed of, which may be causing the compatibility problem with the X25-E.
The Intel IRST driver (for Windows) has a UI that will display the negotiated SATA link speed.
FYI, all SanDisk SSDs, at least the models sold in the US, use SandForce controllers. You wrote SanDisk in your first post, and later Samsung, so I don't know if you meant one or the other, or both.