How bad is Error Rates in HDD?

Solution 1:

CrystalDiskInfo is labelling the disk as "Good" because it has no bad sectors.

However, the Read Error Rate is 83.

The counter is described as:

Read Error Rate S.M.A.R.T. parameter indicates the rate of hardware read errors that occurred when reading data from a disk surface. Any value differing from zero means there is a problem with the disk surface, read/write heads (including crack on a head, broken head, head contamination, head resonance, bad connection to electronics module, handling damage). The higher parameter’s value is, the more the hard disk failure is possible.

Recommendations

This is a critical parameter. Degradation of this parameter may indicate imminent drive failure. Urgent data backup and hardware replacement is recommended.

My conclusion: Your disk is aging and replacement is advised before it fails. The slowness may be caused by read error and retries, which do manage to finally recover the data (so no unrecoverable errors).