Just to put in here for nForce users, nForce boards do not support AHCI (with the exception of nForce boards that include onboard graphic cards), and also don't send the TRIM command for SSDs. It can do NCQ through its controller though. The JMicron SATA ports do support AHCI, but you'd get worse performance running a HDD through these, than on the normal SATA ports.
You can uninstall the Nvidia controller though in Device Manager and install Microsoft's IDE Controller, which can send TRIM commands for SSDs.
Head to Device Manager (Open Start menu, type Device Manager), and click "IDE ATA/ATAPI Controllers", and you will see 3 Nvidia Serial ATA Controllers. Right click one of them and click "Properties" and go to the "" tab. Click "Update ". Click "Browse my Computer", and then "Let me pick". You will see the option to choose "Standard Dual Channel PCI IDE Controller". Click this and click "Next" and let it install.
Do the same for the other two Nvidia Controllers in Device Manager and restart your system. After the controllers have installed, you will be asked to reboot again.
SSDs will now have a slight performance boost with the TRIM command, and also regular HDDs also have a slight increase as well.