Have you tested the drive using SMART? SMART is not exactly infallible if it says that the drive is OK but it is 100% accurate if it says the drive is failing. If you have access to TechTool Pro or TechTool Deluxe, you could also run a surface scan although that might take several hours.
Unlike other apps that report S.M.A.R.T. status, TechTool Pro reports not only the summary pass/fail or verified/unverified, it reports each of the S.M.A.R.T. parameters current value, and the safe range established by the drive manufacturer.
Drive Genius will do a surface scan as TechTool Pro does, and extensive research indicates a surface scan is by far the best indicator of an impending drive failure. Empirically it seems as if Drive Genius does its volume repairs in less time and is also faster at defragmenting a volume than TechTool Pro. Surface scan on the other hand is slow no matter what utility you are using. Each of the three major volume repair products have important unique features.
