I should have elaborated more, but W520 comes with "Power Manager" and it has many controls like, "System performance", "Fan control" which includes "reduce noise dynamically" option. It also has system temperature (just a prediction) depending on the option I choose in the Power Manager.
So, when I do the location recording, which requires quiet background, I use the "reduce noise dynamically" option in the Power Manager, and especially use lean DAW like Reaper to record tracks. I just don't use any plug-ins on location and channel count is usually 4-8chs, so the CPU usage stays around 5% all the time during the recording. I can say the fan noise is almost dead silent. If I still hear the fan noise, I use long mic cable to put them far away from the mic, and also put the computer in a large carrying bag, and operate inside the bag. By the way, I also run DPC latency checker at the same time, just to make sure this "reduced" power setup doesn't cause any spikes.
My CPU is 2820Q i7 processor with 8GB RAM.