Since someone had deleted your drive model #, I can’t be sure whether your drive is USB3 compatible or not. If your drive is USB2, and on of current release of My Passport, then your drive may be suffering from sleeping disorder.
There is no proper solution available right now. (Current firmware release won’t fix this)
There are workarounds to keep this drive100% awake (Manually modifing APM parameters with Crystaldisk). Read previous posts. I persnally don’t think that is very healthy for a 2.5 drive without active/passive cooling.
But if you’re reffering to little slowness on read/write performance, then you have to wait until WD fix it with newer firmware release. I have notice that too.