Hard Disk Monitoring

I see this type of report quite often when I test SSD's or M2's. Is this normal?
Thanks,

Yes, this is normal.

Generally the darker green blocks reflect that the affected part of the disk drive is slower than expected, slower compared to the previous sectors/blocks tested (which displayed with normal green color).

SSDs may have high amount of cache memory to suggest how fast they are. But when the cache memory is filled, then the SSD needs to perform with the "real" speed - which is much slower. So while the cache is flushed, the SSD is generaly performing slower. This results in a periodic darker green pattern: sometimes the SSD can be faster - sometimes seems much slower.

Generally manufacturers select the size of the cache to big enough to

- suggest that in normal daily use (when we do not write 100's of GBs) the SSD should remain fast and responsive enough
- mimic benchmark programs which uses a LIMITED amount of data (compared to the complete capacity). They may only work in the cache, without performing real I/O (or performing part of it only).

This is why generally Hard Disk Sentinel has no quick "benchmark" function, but offers exactly THIS method (complete surface scan) to detect and verify the REAL performance of the disk drive.

Similar may happen with most flash storage (SSDs, pendrives, memory cards too).

This does not mean that the particular sectors displayed with darker green color are faulty, damaged or slower. If you would try a different test order in Hard Disk Sentinel, you may receive a different pattern, not always the same blocks would be displayed as darker green.

You can try: select Disk menu -> Surface test -> the test type and the device but before starting, select the Configuration panel. There you can enable
- Sequential Backward test
- Random test
- Butterfly test
and un-check the default enabled Sequential test.

This way the sectors would be processed by different order, exactly confirming the situation (that not a particular area is slower).

Thanks for the info....