guess the days of daughter boards and removable graphics chips died out long ago!?! From a laptop manufacturing view they wanna sell you whole new systems, not upgrade them?
How do you want to improve game performance?
load times = HDD dependent, but a little sd card with readyboost might help.
fps = unfortunately you going to have to play games at less than high settings to get the highest frames out of your laptop.
IF your laptop has access to the soDIMM ram slots on its underside, you 'could' get more RAM, but you would need to check what your laptop supports, and how much you can add (and it will cost).
There is not much you can do. The vast majority of laptops only allows you to upgrade the RAM and storage. Though there are ultrabooks and 2-in-1 laptops that do not even allow you to upgrade those things.
Laptops that allows you to upgrade the GPU are limited to specific gaming laptops that typically starts at $1,400 which have MXM format GPUs. The MXM GPUs themselves can be pretty expensive themselves and they are not sold directly to consumers.
If you want better performance, then you simply need to buy a newer more powerful laptop. The performance increase must justify the cost of the new laptop. For example, the 940mx is more power than the 840m, but the increase in performance is very small in comparison to buying a laptop with a GTX 1050.