There are different kinds of Radeon, so it depends on what you comparing. The OEM 64 MB and 32 MB are usually clocked at 166Mhz or less, while the LE is 148Mhz I believe. The VE is just different than the rest, so even if you overclock you won't get it to be as fast as the others.
And yes, the OEM usually don't have a fan, and the 64 MB may not have TV in/out features.