Get 1 stick, but due to high costs 3200MHz isn't worth investing as the performance improvement isn't much (actually not even observable). Get 2400 or 2666 as they are the sweet spot. Invest money on other components like higher capacity SSD maybe.
In a way 8GB is considered as minimum for PCs. So no point in having 2 4GB sticks. Get another 8GB stick after few months & you are good for next few years.
That is true for discreet GPUs since they have their own dedicated higher bandwidth Gddr5, but IGPU depends on system memory which has less bandwidth . higher mhz help
Dual channel is farrr more important .. you can loose as much as 40% performance if using only single stick as shown in that video
From the videos i posted in my previous post of 2400G , from 1 of the frames 2133- 33FPS , 2400 - 36 fps , 2666- 38 fps , 3000- 40 fps , 3200 - 42 fps
Considering price and budget , i think 3000Mhz is ideal , and 2666Mhz is minimum for IGPU
Sling shot if IGPU performance doesn't matter / or playing very light/old games until you can buy an additional stick to make it dual channel , then go with single 8gb stick .. otherwise if you want IGPU performance now , then you will have to go with dual channel
and do check it on Motherboard qualified vendor list and see whether ram is supported to work at higher speeds or not.. as early on they had issues although most likely should be fine by now with recent BIOS updates.. but still confirm first before buying
