DOTA2 low fps during hero picking phase

Question

Usually I have ~50FPS rate, but when I picking hero in PvP game (with bots it works great), my FPS downs to 9-10 and sound is cracking.
Before I played well, in common I use proprietary driver, but some days ago, when I reinstall system with encryption, I also tried non-proprietary driver, which was bad idea for my NVIDIA GeForce 9600 GSO (too many artifacts and very low FPS).
So I deleted "free" driver and installed proprietary driver. Mb I forget to delete some free-driver packages, or forget to install some non-free driver componets, mb some libraries (provided by Steam) are conflicting with system`s librararies. Anyway I dont know what to do, my attempts to find a solution in Internet led me here.
I`ll be very greatful if you help me! But you must know that I`m not a Linux-guru, so write me all commands I need.

Answer 1

First of all, whether you have  1GB/512mb/256mb of vga memory doesnt mean much in terms of performance, it all depends on your specific gpu unit whether its a 5650M, 6570M, etc. In your case your gpu does seem to be able to run most older games okay. Measuring fps in lobbies doesnt mean much either since there's hardly anything there for your gpu to render. You say you begin with 60fps and then drop to about 20fps midgame, presumably when the action is getting most hot. You could perhaps try lowering your graphical settings a bit or maybe your resolution. Alternatively the problem may also lie with your internet connection.