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My mb and cpu temps are higher with more powerful fans!!

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Dec 30, 2000
I have an Antec sx830 case with the two included fans in the front (don't know the specs). I had two regular Sunon 80mm fans in the back. My mb temp was 21C and the cpu @ 26-27C...so then I got greedy and exchanged the Sunons for "high output" Sunons (+6 cfm vs. regular) and now my mb temp is 22-23C and cpu is 29-30C...is it possible that by putting the more powerful fans in I now have an imbalance of airflow? Should I go back and get the regulars? They are 4-pin fans so I can't check the rpms but they seem to be working fine...I just want to know if my thinking makes sense...thanks.

I'd just put in whatever's coolest.

I have some very expensive cooling here and I'm using a cooler made from a broken Alpha PEP 66, some PolyMethylMethAcrylate and a Sunon 40CFM 80mm fan - it cools much better than any of my nice new toys, but looks horrible and sounds horrible.

I don't care though - whatever does the job most efficiently.
If you had more air going out the case that would give a negative case pressure, which I guess in an extreme situation would mean that temps could rise, as there is less air to transfer heat to. Dunno if this reasoning is right/wrong, it's just a suggestion... also could be the powerful sunons are stealing air from your heatsink's fan, reducing the airflow over it - not sure whether this could be possible, but if the fans and hsf were in the right places it could happen - I used to have a psu that was stealing air from my PAL6035, and covering some of the intake holes on the psu side lowered temps by a couple of degrees.

Now I just ran a little test where I unplugged one of the two back fans to compare the temperature and it's exactly the same as with 2 fans running!! It doesn't make sense...do I just have more firepower than I need? Please shed some light on this!!

That's pretty weird, my first thought is to make sure they're all blowing air the way you want.. Though, I doubt that's the problem. I would have to say yes-you can have too much cooling.. Once the case temp gets to just a touch over ambient, you aren't going to get much more by adding more fans.. A nicer HSF perhaps, or water cooling, and such.. 21C for a mobo temp is very impressive though, I say stick with that setup.
Sometimes you can get dead spots in your box where the air continues to circulate inside, picking up heat, instead of exhausting. You can try rounding your cables and moving them out of the way of air flow, tucking away your power cables, etc., to try to maximize your cooling. If you have the room by your mobo and CPU, you can try putting an exhaust fan(even if you have to cut your case). close by to get rid of the hotter air generated. If you do a bit of searching, you can find different sites that really get into a lot of deatil about fans and airflow.