What is ECC Memory and Should I Get it for my system?
ECC stands for "Error Checking and Correction". It's a technology that allows the memory to not only detect memory errors but also correct them on the fly.
Some of us who have been around computers longer may remember the old parity memory that used to be on sale at a slight premium over regular memory. ECC and Parity memory share some likeness in that both can detect errors in the memory, however, ECC takes it one step further by correcting the error and preventing it from affecting your application.
ECC is for servers
Realistically, ECC is something only a server or mission critical system would need (sort of like Registered Memory) because memory errors are very rare and because the number of errors likely to be experienced by a system is proportional with the amount of RAM on that system - since servers tend to have a few Gigabytes of memory, and because they are on 24hours a day and also deal with huge amounts of pretty important data, it's not hard to figure out why ECC is considered a must for any serious server application.
ECC Slows down Boot time
Another reason why you wouldn't want ECC in a regular system is because once ECC checking is enabled you better be prepared for the longest RAM check you've ever seen in your life. It is literally several times slower than regular memory checking during POST.