What could cause slow speed transfers between hard drives?

[sigm4]

Whenever I transfer files from my SSD (Evo 850 120GB) to my HDD (WD Green 2TB) it starts with blasting speeds as high as 400 MB/s then seconds later it drops to 50-70 MB/s, what gives? Thanks!

 

[GhislainG]

400 MB/s occurs while writing to the disk cache only. Are you transferring large or small files? That performance is normal for small files.

 

[SuperSoph_WD]

Hey there, sigm4!

@GhislainG is totally right! So I'd recommend you to try copying some large files as well just for the sake of troubleshooting and see how the speed will be then. If you have any concerns regarding the SSD, you should follow the link to this thread with some SSD diagnostic tools you can use to test its health: http://www.tomshardware.co.uk/answers/id-1926483/ssd-diagnostic-tools.html
As for the WD Green, I'd suggest you to use WD's Data LifeGuard diagnostics tool to check up on its health and SMART status. Here's a link to the utility: http://products.wdc.com/support/kb.ashx?id=ssdzl0
Though I doubt there's anything wrong with them, it's good to have those drive monitoring software tools.

Hope I was helpful! Keep us posted though!
SuperSoph_WD