I just cloned my xp media center sata laptop hard drive onto a samsung 840 ssd. It's working fine. The samsung magician software said I should be in ahci mode, though, for better performance, and I went to bios to check but there is nothing there about changing to ahci mode. Is this really necessary? If so, how do I do it if there is no indication in bios?
If your motherboard is old then it won't support AHCI mode. That would be in the part of BIOS where your SATA drives are set up. However, if your cloned disk of Windows did not originally use AHCI to access the hard drive, then if you were to change it now Windows would BSOD on you because it would be using non-AHCI drivers to access the AHCI hard drive. So the short answer is, the only way to use AHCI (assuming your BIOS supports it) is to re-install Windows from scratch.
Well, not sure how old is considered old, but the laptop is an Averatec 2370 and I have probably had it for about 6 years. The original hard drive it came with is what I cloned, and it was a SATA drive. Would rather not reinstall windows since I am happy with my installation and don't want to have to reinstall all the programs, which is why I cloned in the first place. So my basic question is, will this make a difference? Is this going to shorten the life of my ssd drive or reduced the efficiency in any significant way?
Most SSD's have some sort of garbage collection, but without AHCI windows won't be able to send the TRIM command to the SSD. In your case I don't think it matters much since XP doesn't natively support TRIM anyhow.