best hdd benchmark tester

Hi guys.
Im fairly new so im wondering if anyone can point me to a good software, Im looking for a hdd benchmark tester. Free if possible i have a couple of backup drives i would like to check out.
Also while im here. Last time i checked up on one of my back up disks i did not get a reading for writing to disk. but read rate and access time were fine. the disk is not writer protected and has performed fine.Anyone any Ideas?