Probably the fan speed is to slow. Nortmal the default setting is for "silent". Just open the overdrive window (as you plan on) and set it up to 4/50 %. Recheck with a program to verify it jumps up, I use furmark. I think there is a setting to base fan speed on % usage.
IMO, 4xxx series ran particularly warm, although it's not dangerously high.
More importantly, what temps are you getting @ load? If you are getting >80C, then you need to consider better cooling.
Remember, most cards are rated @ 100C, but you want to keep it as cool as possible for performance/longevity.
1. Was it always at this temp?
2. How big is your case?
3. Does it have good airflow?
4. Do you have good cable management?
5. When was the last time your cleaned your case/card?
1. Was it always at this temp? It's idle temp(56-58) When i use Furmark it goes up ( 80-85 when i run it for 5 min.)
2. How big is your case? Small i think.
3. Does it have good airflow? It has got one fan on the side. And Graphic card has its own fan.
4. Do you have good cable management? I have just bought a new PSU so cables are free now.
5. When was the last time your cleaned your case/card? I didn't try to clean it. Sometimes i just wipe in it with a cloth But i have never tried to clean on motherboard etc.
(1) 75% is OK as long as temps are OK.
(2) The fan on the Side, is it intake, or Exhaust - Where is it located on the side panel?
My prefernce on fans is on at the rear (Exhaust and one on the front as intake. If the side is located top/rear of case, I would still add on on the rear. If side fan is centered on the side and is an intake, add rear. If centered and exhaust, chant to intake and add rear fan (exhaust). Also if posible add front intake - Not all cases allow for a front panel intack.