Graphics card upgrade

[Gingrr638]

I have a Lenovo h520s and I'm told I can only use at max GeForce gt 640 so it will fit my case. I've done some looking and the gtx 650 has the exact same dimensions. Is there any other reason it won't fit?

 

[TomTom111]

if they're going into a pci express 1, 2 or 3.0, then yes. Dimensions would be your only limiting factor.
What size case is it?
I currently have a GT 650 in my GFs ATX mid tower with plenty of room for a full sized 11" card.