What is better to choose to speed up a macbook?

Question

macbook

macbook pro 13" 2012 non-retina 4gb ram
slows down
the user works mainly in browsers with a bunch of tabs

and no money but we hold
on the owner wants to upgrade in two steps
if you choose only one option first of these two then what to choose? -

1) dust cleaning and replacing the thermal paste + replacing the RAM with 8GB
2) adding an ssd and installing the system on it

I have an aimak 21 "2013 - it has an HDD of the same speed but 8GB of RAM
, there are no brakes,
so I think that the main thing is adding RAM

Answer 1

Elcapitan system

Refresh.

1) cleaning dust and replacing thermal paste + replacing RAM with 8GB
2) adding ssd and installing the system on it

Both options.

Answer 2

Both options. Reason - hdd 90% that is already killed