It says you only have 1 cooling fan because you have the one hooked up to the aux or system fan connector on the mobo. You should try to get that fan connected directly to the power supply like the others. Drawing additional current through your mobo doesn't help you. connected to the mobo is why the monitor sees it. Have you left an open PCI slot next to the graphics card? You should if you can, it gives better air flow around the card that helps it stay cooler.
There are a lot of different case fans to choose from. What you need to decide is whether you want cooling or quiet or in between. You need to look at CFM or cubic feet per minute to see how much air the fan pushes. Also you need to look at dBL or Decibels, the amount of noise the fan makes. The Vantec Stealth 80mm fans push 27CFM at 20dBL. The Vantec Tornado on the other end, pushes 80+CFM at 55dBL which is really loud. It sounds like you are running a power generator under your desk. It also draws enough power that most recommend you don't connect it to a mobo fan header at all. Those are the extremes. You can get the 80mm case fans in different thicknesses 80x80x20mm or 80x80x25mm Most are 25mm.
I use only Sunon fans. KD1208PTB2s 80x80x25. They run at 37CFM at 32dBL. That's about the bast noise to CFM ratio out there. Or was the last time I bought any. If you are into lights and modding your case they only come in black. Sorry. I also have the metal mesh work on the case where the fans connect behind, cut away. It cuts down the noise and increases the air flow. The fans are pretty much silent. If you took the blades off and just ran the motor you would probably not hear anything. The noise a fan makes is actually being produced by the air moving. I also have a side intake. I installed an 80mm to 120mm adapter, and have a 120x120x38mm Sunon there that pushes 98CFM at 36dBL. You can see that the larger the fan the more efficient CFM to dBL ratio you will get. Anyway 100F or 38C for the system is not really that hot. Especially when you have a high end video card in there.
I'm sure you have done this but make sure your case fans are installed the right way. Tear off a little strip of kleenex and hold it in front of your intake slot on the case front and make sure it gets sucked toward the case. And do the same in the rear making sure it gets blown away.
About you mobo fan connectors. There are 3 marked fan but actually you have 4. Look in your users guide and make sure the chipset fan is connected to the J10 connector. Don't even use the chafan1 or pwrfan1 connectors. And of course the CPU fan goes in the cpu fan1 connector next to the socket. What kind of speed are you showing for your chip set fan. It should be twice the speed of the CPU fan.
