ive just installed a few case fans one intake at bottom front two exhaust fans at top rear of case and one exhaust pci slot fan directly under graphics card which takes the heat from heatsink on graph card and exuasts it out the rear of case my question is this if the 2 rear exuast fans are sucking air out...and the cpu fan is blowing air into the cpu heatsink....then surely the cpu fan will be fightin for air air between the 2 exuast fans

The idea is that the exhaust fans take the heat away from the cpu heatsing. Kind of like this Air Intake -> Throught CPU Fan onto cup -> Out through exhausts. Heat rises.

i see the idea... but with the rear case fans mounted near the cpu fan (both turning opposite directions (exaust blowing out...cpu fan blowing on cpu) then i cant see how the exaust fans take the heat away from the cpu when its own fan is blowing it away from exaust fans

you can switch the direction of your CPU fan, to blow air away from CPU instead of onto CPU... same cooling efficacy, and more logical given your setup

nice one...so how can i switch the direction the plug in the mobo is a 3 pin ....wires on the fan are wired directly into fan

Tomo, <<if the 2 rear exuast fans are sucking air out...and the cpu fan is blowing air into the cpu heatsink....then surely the cpu fan will be fightin for air air between the 2 exuast fans>> You are amongst a few who point this out correctly. As for CPU fan blowing away from heatsink, Alpha and the new Kamakaze are the only two that I know, both using "pin" rather than "fins". There are advantages and disadvantages (blowing away versus blowing onto the heatsink); blowing onto the heatsink allows cooler air to effect NB and MOSFETS; blowing away is like you describe in assisting the exhaust. This is the reason behind this article: http://www.home.earthlink.net/~lazyman/data/SWChillvent.htm

good link lazyman so lets look at this way the chill vent seems to work well... so if i cut a round circle in the side of my case....enough for a white plastic drain pipe to fit through then attach a round to square end on it and place it over the cpu as like the chill vent does...attach a 80mm fan on the other end of the drain pipe....this will bypass all the hot air thats circulating in the case and blow cold air directly from outside onto the cpu. i could also (thinking about it)attach a small tumble dryer vent through the wall to outside the house (only 1 foot away from the case)and have the flexi tube running directly to the newly created chill vent tube into the case and supercooling my cpu. thank you lazy...you have given me food for thought