I've installed a SSD on my Dell Vostro 1710 on a clean install of Win 10 and disk is running at 100% almost all the time. This didn't happen on the HDD that was installed previously. When you look in Task Manager while it reports 100% you can't see anything specific hitting it hard (as you would expect to report ....)

Vostro 1710 is on latest bios A12
Micron MX1300 256gb SSD with latest firmware

Clean install of Win 10 Home, updates installed and both times it very slow as at 100% disk use most the time. I've put the same SSD in another laptop, clean install and it worked well. I've check SMART drive info and the SSD is all good.

I installed Ubuntu on the SSD in the Vostro 1710 and it ran very well so it feels like a Win 10 issue rather than hardware.

I know the Vostro 1710 is only SATA 1 but the SSD should be faster than the HDD, it currently not. I've put SSD in Dell of similar era on SATA 1 and it's made a big improvement on performance.

The CPU isn't running hot and throttling, I've check the thermal paste is all ok.... 

I'm running out of ideas on what check and how to fix it?