you're right, stock cooling is simply the heatsink that comes with the card
increase the clock, then do an artifact test... this way you'll know where you start getting unstable
you wanna increase the GPU clock first... this is the cycling frequency of the GPU core... after you've hit your max core clock, you can go on to increase the memory frequency (which refers to the speed at which the memory bus is addressed)
oh yeah, the issues you've got with Spiderman is not a GPU problem... its more than likely a driver level issue. have you got Hydrid CFX enabled? are you sure your 4870 is set as the primary graphics adapter?
I kn ow that im using the 4870 because i saw a major difference from when i used my hd 3200 (like 50 Fps difference) , but when i go to can you run it, it says im still using my hd 3200, how will i be able to set it as my primary graphics adapter, and as for the hydrid CFX.. i dont know what that is (sounds something like crossfire?, I dont think you can crossfire an hd 3200 and a 4870... or can you?) sorry im very noob at this. I just simply installed my gpu and installed the drivers on the cd with the updates.