It's more than that...

Most server memory should be registered (holds the data in registers for 1 clock cycle for better reliability), and error-checking and correcting so when (it is when not if) a bit error does pop up it fixes it on the fly.

Even hard drives are different. For example western digital's "RE" series have different firmware than desktop drives. The "RE" drives have a different error recovery setup. They limit the time to attempt recovery at the drive level moving the intelligence to the controller... Why is this important? ... because if there is a problem, with a desktop drive the controller is signifigantly more likely to drop the drive out of the array (fallout). Did you know that most drive manufacturer's won't support a non-raid drive in a raid setup? While it will probably work, if you have issues your on your own.

Personal boards, firmware, etc. for servers tend to be designed more for rock-solid 24x7x365 operation while desktops tend to compete on numbers... oh this model turns 9998 uselessmarks, where that one only does 9800...