37c at idle?? YIKES! thats a bit warm, if you ask me.
First thing I'd do would be to reverse one of those case fans so it's blowing out. You need to get the hot air out of the case as fast or faster than the cool air coming in. Think of it as a car. Let's take a Camaro, an extremely "overclocked" car...... Yank off the cast iron, 2 BBL intake manifold, and put on an aluminum, high rise, put a 6-71 blower on top of that w/ dual carbs on top of that. You have significantly increased the flow of air into the engine. More power, right? Not if you leave the pedestrian Generous Motors exaust on there. You wind up w/ lots of backpressure, because the air can't get out of the engine as fast as it gets in. Same church, different pew........Thats why they sell so many of those "turbo" mufflers. Less backpressure.
The best way to set up the case fans are to have as many or more blowing out than in. I have one fan on the front of the case blowing in, and two on the back, blowing out. My case temps run about 3-5c over room temp, and the cpu (Celeron 600 @ 1008) runs 27-28 at idle, 37-38c under load, at 2.05v.
Try turning one of those fans around for a bit, and check your temps. I have a feeling they'll drop a bit.
Mr B