Well i've had this Alienware M17x R3 for a little over a year now and it was running fine till April/May this year, all of a sudden lag spikes that last a minute with a 20-sec Cooldown, dropping framerate from 60-120 to an average of 5-20. I have ran a full registry check and virus scan and still hasn't been fixed, rolled back drivers, rolled back the system, nothing has fixed it... Any help would be appreciated!
What are your temps? Sounds like your gpu is throttling due to heat. Get hwmonitor, launch it and leave it open. Then play something a bit until you see the drops you're talking about, exit the game and bring up the hwmonitor window. Check max temp of the gpu, report back. You may need to repaste the gpu or CPU of temps gets too high.