are buying another 4gb is worth it?

[wolframazer]

I have a single 4gb ram hyperx ddr4 2400mhz, my build is intel g4560 and gtx 1050 ti, I only play few online games, like dota and roblox, but when I play dota 2 and the teamfight begins and there are heroes on my screen like pl, ck, meepo and naga, the fps drops to 53, even in replay I close my browsers I don't multi task I see the dota 2 eating 1gb ram or more on task manager. was getting another ram to make my setup 2x4gb will improve the performance i mean dual channel? or I should spend my money on gaming keyboard like hyperx alloy fps pro tkl cherry mx red, because my fingers hurt on membrane keyboard, I just use my pc for watching, browsing, and casual gaming

 

[geofelt]

Likely, 8gb would help.
Look at task manager and the hard fault page statistics.
If you see a significant number, like >1 per second, then you are short of ram.

The dual channel aspect will be only a minor help.

But, consider carefully about adding another stick.

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
The internal workings are designed for the capacity of the kit.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, can be very sensitive to this.
This is more difficult when more sticks are involved.
That is why ram vendors will NOT support ram that is not bought in one kit.

If you do buy more disparate sticks, they must be the same speed, voltage and cas numbers.
Even then your chances of working are less than 100%

What is your plan "B" if the new stick/s do not work?

Intel is quite tolerant of disparate ram. I put your odds of success at 90%