WD Black WD10JPLX - very slow


I bought new WD Black WD10JPLX. Install in Acer V5-573G.
But HDD work very slow and sometimes loop for few second.
For example, installing Win10 lasts about 3 hours from start to show desktop. And after that another 3 hours to installing updates and few drivers.
Average speed of reed or write is 20 MB/sec. Sometimes its 80 MB/sec, sometimes 80 kb/sec.
Then i connect drive to PC, load from another HDD and run few tests.
DLGDIAG long test don’t show errors, but elapsed time for long test is 12:41:26.

I want know, is this a defect or what is wrong.
Thank you!



What test did you ran with the DLG tool? if it was the quick test, try running the extended test.


I run both tests.
Extended, as i say, pass in 12:41:26.
Quick test pass in about 30 minutes.

I return HDD to shop and now wait for resualt of service.