Great, thanks very much :) I've just ordered the AMD Athlon II X4 645 so I'll see if that works. Thanks for your help :)

The Athlon II X4 is an AM3 socket and the Inspiron 546 is a AM2+ socket.  So it may or may not run and if it does it won't run at full potential.

Oh right - I thought that AM2+ would be fully compatible with the AM3 sockets too?

Hmm...rethink then!

Well, just phoned Dell....they weren't any help at all.

Refused to tell me which processors would be compatible with the motherboard - instead he insisted that I shouldn't upgrade the processor!

what you should try is the amd phenom II x2 560 black processor which is a quad-core with two of the cores locked for your own protection ) Most everyone I have talked to, including myself. has unlocked the other two cores and for the price of a dual-core you get two extra bullets ) the phenom is just slightly slower than the i3 and i5, but doesn't heat up as fast as the 2nd generation intels--i7 is a monster but expensive )  --toomuchjavaman

Thanks for the recommendation :) is that this product: www.scan.co.uk/.../amd-phenom-ii-x2-560-black-edition-callisto-core-s-am3-33ghz-7mb-cache-ht-4000mhz-80w-retail

If so, if the processor I've ordered doesn't work as well, I'll exchange it for this one

So, did the AMD Athlon II X4 645 work in your Inspiron 546?    I've got one of those boxes with the same MB as you, with the latest firmware installed, and would like to know if that CPU will work with it.   Thanks in advance if you see this post.

Hey,

No, the processor didn't work. My advice - buy a new motherboard. Dell flatly refuse to offer a CPU compatibility list for this motherboard and it's more trouble than it's worth trying to get something to work with their board.

Thanks.  I was just getting ready to order one and checked this thread to see if you'd replied before risking it.

Did you upgrade your BIOS firmware to the latest version first?

I've seen some posts that the some of the Inspiron 546 PCs shipped with the Athlon II X4 630 in it, and I remember seeing one post from someone that said an Athlon II X4 640 worked in one.

So, I'm surprised that the Athlon II X4 645 didn't work unless the BIOS wasn't updated to the latest version or there is more difference between the 645 and the others.

Do you know what motherboard revision and BIOS firmware version you tried to use with that CPU?