Theres a lot more to resources than what the task manager shows you. Your video card for starters barely meets minimum requirements. Your hard drive is slower than usual desktop hard drives (5200rpm vs 7200rpm). Your laptop is bound to run hotter than a desktop, and that right there is the biggest performance killer for laptop gaming. Not only that, but your cpu cycles are lower than a regular desktop simply because they arent designed to use up even HALF of those desktops were made for. For example: An INtel laptop quad core wont even touch the speed and performance of a Q6600 Intel quad core because the power consumption is around 54w for the laptop, while the desktop will use 90+w. Not only that, but BF3 and MW3 type games have small maps, and dont have to draw every single building, tree, clouds, water, etc etc... within a 100km radius.
You just cant look at your system resources and say hey, Im only using 80% of the computer, somethings not right. I had a laptop for a grand total of 1 week prior to getting this desktop, and it was an Intel i7 with 4gbs of ddr3 1600 ram and an AMD 67xx video card and this SSD I have on this computer. It ran slower than fossilized dino turd. Not even Alienware laptops are worth getting for these sims.