Okay I am looking to hopefully run a few games off of my external usb 3.0 hdd. I have steam installed on my internal drive and am running spare on space. So my question is if I can run steam games off of my external hdd while having steam installed on my internal.
Steam allows you to add a library to any drive connected to the system(Steam -> Settings -> Downloads -> Steam Library Folders). You may even be able to just move some games over to that folder after it is made, but I have not personally tried that way. You can do a backup and restore of games with the backup game files feature in steam(then remove local content and reinstall the game on the other drive).
USB 3.0 is fast enough for any hard drive on the market, but some externals will have the speed limited.
Please use it with case, it should allow a simple close steam and move some games over and create the needed junctions. With this setup, you should always have the drive powered BEFORE opening steam in the future while games are on the external because as far as steam is concerned, the games are on the same drive as steam.
using a USB 3.0 Port on my PC
I get read speeds that top out at 190 MB/s
I get write speeds that top out at 65 MB/s
Games play smoothly. Load times are good. I dont really see any noticeable lag in load screens.
I did experience lag in the steam application when I initially installed it to the USB stick. So again what I did was put steam on the C drive (SSD) and put all the games in a games library on the USB stick. Works great.
Following games tested without abnormal loading
Deus Ex Human Revolution
Steam world Dig
Sims 3 - Initial load seems to take some time but I never actually put it on the SSD so I have nothing to compare it to.