Playing video speeds up copying

[htonio]

Dear All.

I have a WD Black Series WD5000BPKX 500GB 7200 RPM 16MB Cache SATA HDD working in my laptop (Acer Aspire 7738G with Core 2 Duo P7450 and Windows 7 Ultimate). Recently I had to copy large files on this HDD. It turned out that if I start to play a video while copying, it speeds up the process with about 33%. E.g. copying a 15 GB file from my laptop to an external HDD (USB 2.0) takes 12 minutes normally, but playing a video shortens it up to 9 minutes. Can you please advise what can be behind this?

Thank you,
Tony

 

[Boogieman_WD]

Hey there, Tony.

This sounds pretty unusual. That sort of thing shouldn't affect the drive's transfer speed by boosting it up. However you might have had some backgrounds processes running and the beginning of the transfer which could have caused the lower transfer speed.
Because of the unusual behavior, If I were you, I'd test both drives for errors and bad sectors, just to be on the safe side. For the WD black drive, I'd recommend that you download DLG (Data Lifeguard Diagnostic) from here: Data Lifeguard Diagnostic for Windows and here's a link on how to test your drive with it: How to test a drive for problems using Data Lifeguard Diagnostics for Windows. For the external drive, I'd recommend that you test it with the manufacturer's diagnostic tool or a 3rd party diagnostic tool if the manufacturer doesn't offer one. If anything alarming pops-up with either drive, I'd suggest that you backup any important data which you might have on that specific HDD. If everything turns out fine with the tests, then you could download a benchmark tool to test each drive and see what results you get in order to figure out if anything changes while playing videos, as you say.
You could also use a different USB cable (not longer than 12") for the external drive while doing those tests.

Hope that helps.
Boogieman_WD