I only have good fps when I open the game twice.

[RebelLord]

Whenever I open the game for the first time, it runs at around 5-15 fps. But if I open it again after having already opened it, the second screen runs at around 20-30 fps, and I just get rid of the first screen, it works just fine. Was wondering if anyone knew why this is happening?
I have 150 enemies with the ghost blade and final spark passive skills.
When I do this it no longer connects to steam so I don't get any achievements till i reload the game to the lagging one.