Hey there, @ Zdos123!
I'm sorry to hear about your underperforming WD Blue.
🙁 I'd advise you to back up all your data from the HDD somewhere off-site before you proceed with the troubleshooting, especially running CHKDSK. Once you have a duplicate of your files from the WD Blue elsewhere, I'd strongly recommend you run the QUICK and EXTENDED tests from our
Data LifeGuard Diagnostics for Windows. The utility will help us determine what is the health and SMART status of the drive. If you this is a desktop computer, I'd also recommend you swap the SATA cable and the SATA port where the HDD is connected to the motherboard. A failed connection could also cause such drops in performance in the SATA devices. If you have access to another PC as well, you could try plugging the WD Blue there and see how it will behave.
Keep me posted with the troubleshooting!
SuperSoph_WD