Will SSD perform ok without AHCI?

I'm running a Dell System which from the sounds of it has a crippled BIOS.

I'm hoping to buy an SSD next week however I have no option to turn on AHCI in the BIOS.

According to Dell "SSD does not require AHCI to function. However your system will not be compatible with SSD". Sounds more like an excuse to sell me a new pc.

The Chipset is an Intel Chipset P965 which I know an SSD is compatible with.

So if I can't enable AHCI and still use an SSD, will I not be able to use TRIM functions either?

I believe that the Windows 7 TRIM function requires AHCI.

However, you can run an SSD without AHCI. I have one in a Compaq laptop from 2008 that uses an AMD CPU and nVidia motherboard chipset. No AHCI.

I'm not sure whether the latest Intel motherboard RAID drivers support TRIM, but they have not in the past.

Some SSDs are supposed to have built-in OS independent garbage collection, but I don't know which ones do. Some manufacturers make manual garbage collection utilitiies available, but that seems to be increasingly of the past.

I'm a bit surprised that Dell told you that your system would be incompatible with an SSD. In the past, it would have been more typical for Dell to tell you that they don't support SSDs on your system, which translates to: they didn't sell the machine with an SSD, and they haven't qualified SSDs as upgrades. (Dell only supports configurations that they sell.)

I suppose that there may be some reason why an SSD wouldn't work in your system, but it sounds highly unlikely.

On the other hand, why not use this as a pretext to lose the Dell and assemble your own system? It may cost you a lot in terms of time and money, but it'll make it more fun to hang out in enthusiast forums like this one.

Well if dell didn't design everything to their specs I would have a much easier time replacing parts. Motherboard, case and psu are not the standard sizes so can't easily be replaced or moved into another case! :-( So if I change one thing I'd have to change the lot.

A new build won't be on the cards for a while as I'm on a bit of a tight budget at the moment. I'll definitely build my own next time thought.
Hate the way these manufacturers cripple pcs and put their crapware on too.

Thanks for the good advice though! I'm sure I'll still buy an SSD

I forgot to mention the drives I am looking at are the Samsung 830 or the Crucial M4.