I have my Galaxy 8800GT with the fan pointed downward... the fan on the card does what the Zalman fans do and blow the air onto the fins instead of out...
I installed This Exaust fan right under it to pick up any residual heat... I'm now just a little worried that it might be fighting the gpu fan instead of aiding in residual heat exhaust...
I installed This Exaust fan right under it to pick up any residual heat... I'm now just a little worried that it might be fighting the gpu fan instead of aiding in residual heat exhaust...