Samsung 970 EVO: Magician Said It Was Fine. It Was Not Fine.
A 2TB Samsung 970 EVO started slowing down. Samsung Magician reported SMART health as "Excellent," speed as "Excellent," overall status as "PASS." The customer bought a new drive to clone to. Then the 970 EVO stopped showing up entirely. PC-3000 found 9MB of bad sectors that Magician never checked for. This 2.5-hour video is the full recovery.
Why Magician Missed It
Samsung Magician checks SMART attributes and runs a brief speed benchmark. SMART attributes are voluntary reports from the drive's firmware. If the firmware's error correction code (ECC) is handling bad sectors without escalating past the alert threshold, SMART stays green. The speed test reads a small sample of sectors; on a 2TB drive with 9MB of scattered bad sectors, the odds of the test hitting one are near zero.
Magician has no ability to do what PC-3000 does: read every sector on the drive and track which ones fail. It reports what the firmware tells it, and the firmware was masking the problem.
The Recovery Process
The 970 EVO connects to PC-3000 via an M.2 adapter. Samsung's proprietary controller has limited native support in PC-3000 (no firmware-level access like Silicon Motion controllers get), but basic sector-level reading and extraction still work.
First pass: sector-by-sector scan of the full drive. Approximately 900MB of sectors were skipped on the first attempt. The PC-3000 sector map showed concentrated zones of bad sectors that Magician never tested. The technician identified 42GB of critical customer data using the file tree viewer and configured a targeted extraction.
Second pass: increased read timeouts and 5-10 retry attempts per failed sector. Degraded NAND can return readable data on a second or third attempt that it refused on the first. Sectors that were black (failed) on the map started turning green (successful).
Third pass: aggressive retry with power cycling between attempts, different command sequences, and up to 20+ retries per remaining bad sector. Final result: 42GB of customer data recovered with only 38KB inaccessible. That 38KB turned out to be non-critical system cache. The recovered data was transferred to the customer's new drive and the system booted cleanly.
The Speed Lie
During recovery, PC-3000 displayed live read speeds. Healthy sectors read at 20-27 MB/s (normal for recovery mode). Degraded sectors dropped to 200 KB/s or lower. Magician's speed test showed the drive at full rated performance (3500+ MB/s) because it only sampled healthy sectors. A 2TB drive with 9MB of bad sectors is 99.9995% healthy by area. A random sample will almost never hit the bad parts.
Samsung Magician Says Your Drive Is Fine?
It might be. It also might have 9MB of bad sectors that Magician will never find. If your drive is slowing down, freezing, or disappearing from the system, trust the symptoms over the diagnostic tool. Send it to us for an actual sector-level evaluation.