Case Fan question

[richlevy]

My underpowered computer appears to be getting hot, so I picked up a fan today. Actually, I picked up an 80mm and 120mm fan because I could not decide what the cutout in my computer took. It actually appears to be a 90mm, so I was able to get the 80mm to fit with a washer I found and some determination.

I have two questions. My computer uses an A7V8X-LA (Kelut) motherboard. The only fans that were on the board were a CPU fan (circled in red) and the power supply fan. The fan I added is circled in yellow. The white elipse shows the vents at the bottom side of the case.

Should the case fan be exhaust or blow into the case? I currently have it set to exhaust assuming that cool air would be brought in through the vents.

The Antec 80mm tricool fan came with no instructions. I have it hooked up using the provided 3-pin plug hooked the the 3-pin case fan supply on the motherboard. Antec also provided an adapter to the 3-pin fan plug that split into a 3-pin to the motherboard and a 4-pin pass through that would share power with a CD or hard drive. Right now the fan is hooked to the motherboard directly and is working. What is the advantage of using the adapter to hook to the motherboard and a 4-pin power supply plug?

The tricool comes with a manual 3 speed switch in back. When I set it to high or medium the fan is on. When I set it to low it turns off the fan. Anvir reports that my computer temp is 104 degrees Farenheit. This is with the side of the case off.