What causes YLOD?

[eybic]

What causes the YLOD on fat PS3's? I currently have a 40gb one and have (so far) had no problems with it and am considering putting a big hard drive in it. Does the HD cause the YLOD or is it something else?

Basically, should I put a 500gb HD in my old fat PS3 or buy a slim with small memory and upgrade from new?

Thanking you kindly

[eybic]

Thanks guys,

There are no issues at prese nt I just want a bigger HD. Just need to get myself a cheap external HDD for back ups.