Changed steam directory framerate drop in games

[laynepet]

computer specs:

500 gb WD hdd
128 gb crucial ssd
8 gigs ram
i5 3.1 Ghz ivy bridge processor
nvidia GTX 550 Ti

I have diablo 3 installed on my hdd and it has run fine on high for about a month. The other day when i bought fallout new vegas i had to download steam. I installed steam to my ssd and fallout ran fine for about 30 mins. But, i decided to move my steam download from my ssd to my hdd so i deleted all of the files except for the steamapps file and the steam.exe file. I moved it and redownloaded the rest of the files steam needed. But, when i went into fallout my frame rate has now dropped to 1-5 fps. I decided to open diablo and see how it did and is also has this problem. Both games have become unplayable. What could have caused this kind of slowdown?

 

[laynepet]

Ah a simple restart fixed the problem. I shall read other posts first to see if it answers my questions. But if i may ask, what causes it to slow down so drastically?