I am using this Vostro 3460 (with Nvidia GeForce GT 630M 1 GB Graphics) for near about a year. I usually play games like FIFA which uses the graphic card moderately. I have experienced almost noiseless exhaust fan for first few months after my purchase of this laptop. However, recently it usually gets heated up quite regularly even if I am only browsing the web or play videos. The fan becomes EXTREMELY NOISY understandably running at full speed and takes a very long period to cool down. I have my laptop on a laptop stand to make sure that the hot air gets passed not just through the vent along the cooler but also through the small vents under the processor. Nothing seems to be favoring me that much and I am getting sudden power-offs (with the AC power cable plugged in) when the machine really heats up a lot. The fan used to perform almost silently before but now, even if the machine is idle, there's a moderate level of noise.
I still have a month left in my warranty.