I bought an Alienware 51m R2 and am having fan problems. 

When the computer was first delivered I was able to compare my fan noise to my friends computer who had the same model. Noticing that I had an irregular noise I contacted support since I had paid for the support package. The Rep completed my support request without helping me!  When I emailed again I was ignored by this rep. Doing my own research I found out that this was a common problem with Alienware components now being shipped. Internet said that Dell had opted to use plastic components instead of aluminum. Although I don't know if this is true, now my fan has completely failed, and I am extremely disappointed in my purchase and overall support by Dell. A $1000 dollar machine with a support package shipped to me defective, and I was never helped. 

What an impression!