Will it improve if I upgrade my laptop's ram to 8 gb?

Not much. Plugged in AC, the 8750m should have at least a gb of its own. It has a 2gb maximum access.
A GDDR5 2GB would be the highest level, and 1GB DDR3 would be the economy one.
It is normally not paired with an i3 in the USA, so seems like an India or Russian model.
It is usually paired with i5 M suffix or i7 U suffix cpus
http://www.notebookcheck.net/...147.0.html

Since the maximum ram the GPU can use is 2GB, the most it can allocate from system memory is 1GB, or it has enough of its own. With 3GB left, 2GB is about maximum that Windows versions use, so it leaves a GB already for side operating programs or the game load itself.
You might get a slight improvement if you are running multiple programs while gaming.
The issues are the GPU, not upgradable, and the CPU which can be upgraded if you find one, but it is difficult to know which one in starting with a i3-3110M. Lenovo offers repair guides with part lists and possible a third gen i5 M suffix is right. I thought from 3 to 4 gen, they changed the core logic in laptops. You would need to find a similar Lenovo model with the same motherboard and i5 and then find the i5, and it will maximize everything the HD 8750M can do, but even that may not be worth the cost and effort. PC gaming is designed for tower pcs.

8750M is about r7 240
http://www.videocardbenchmark.net/gpu_list.php It depends if RAM is your bottleneck.
For games it could either be Graphics, CPU or RAM, you can tell what it is by checking task manager when your playing and see how much RAM and CPU your using.
However, as your grphics card is a little weak, its likely your graphics being your bottleneck (depending on what games your wanting to play, you will struggle with high end games with them graphics) dude. It will definitely increase the speed of your laptop. The performance will be increased. At the situations where you used to get delayed by a few seconds or more will be overcome. I recently upgraded my ram from 4gb to 8 gb. Now its running like a beast. Make sure you get the ram from the genuine store and a nice one. Take care. Only if said games are butting up against the limits of your memory. Run task manager in the background to see.

It depends if RAM is your bottleneck.
For games it could either be Graphics, CPU or RAM, you can tell what it is by checking task manager when your playing and see how much RAM and CPU your using.
However, as your grphics card is a little weak, its likely your graphics being your bottleneck (depending on what games your wanting to play, you will struggle with high end games with them graphics)

Dude. It will definitely increase the speed of your laptop. The performance will be increased. At the situations where you used to get delayed by a few seconds or more will be overcome. I recently upgraded my ram from 4gb to 8 gb. Now its running like a beast. Make sure you get the ram from the genuine store and a nice one. Take care.

Only if said games are butting up against the limits of your memory. Run task manager in the background to see.