you need a 4 pin, you can get delta 120mm fans from ebay for about 60% off that cost. Go to delta's website and pick from the catalog and go on ebay and search the model you want. I have suggested foxconn fans, they can be had for $9 a pop. they do up to 3500 rpm and 150 cfm.
So, I ordered a few fans to compare, one of them was this one. For info. even though the newegg.com site states 2.45A = about 30 watts which is the limit for most fan controllers, this one on the back is actually labeled 3.24A = about 40 watts. Probably would burn out the fan header on the S5 if you hooked it up directly. Also, this fan is powerful and loud. Believe it or not, this fan is even louder than the original one that comes with the S5.
yes, this looks like a hurricane (250CFM!). It looks like it comes with 3 pin connector which you can only connect through adapter to molex chain on PSU, not to pins on the miner.
I found another two "monsters' if you want to go for the maximum flow and don't care about sound:
http://www.ebay.com/itm/Free-Shipping-Delta-120mm-12cm-PWM-TFC1212DE-252CFM-12038-DC-12V-cooling-fans-/171630309537and
http://www.ebay.com/itm/Delta-120-mm-5500-RPM-PWM-TFC1212DE-12V-DC-Fan-S1-S2-S3-S4-Brand-New-/271666540843the same fans, but one is coming directly from china and will take much longer.
same on amazon:
http://www.amazon.com/Delta-TFC1212DE-PWM-120mm-Speed-Sensor/dp/B008NZSUPQ/ref=sr_1_fkmr1_3?s=electronics&ie=UTF8&qid=1421099823With these fans you can probably set a record in S5 speed-I am sure that there are quite a few people here who might try