Need some advice on RAM,
So I’ve a laptop with 8GB ram and I am planning on a upgrade, now if I remember correctly I CAN add a 16Gig stick and it’ll be 24gig, but is it a good call to have different sized ram.
PS. Suggest a ram

Current RAM : HMA81GS6AFR8N-UH
Hynix

P.P.S - I’ll obviously add RAM of the same frequency

i've seen opinions and suggestions from this and that side. Some say it's okay to have "wonky" ram, yet some computers have been bitching about it. I once had laptop with 1 plus 0,25 GB stick. it worked- no problem at all.
So safest is to try out on your machine.

Having two different sized ones is certainly possible (on computers with one stick soldered and one changeable it is a must).

When you have two RAM "sticks" with an equal size (and frequency?), your chipset can enable dual channel, which is faster.

It won't hurt. You'll still have 24GB ram. You might lose some speed but I don't think it would be that significant. Ofc try to get a DIMM with decent CL.

Worst case scenario you can always get another 16G DIMM to boost up to 32G.

just noticed your PPS.

If I were you I'd take the more future-proof approach. If your PPS means sticking to 1333 or smth like that I'd definitely throw that 8G away and buy a decent >2GHz, maybe >3GHz DIMM so that I would not have to throw away the same amount of € for another dimm w/ poor freq just to have 32G which are sloo-oooowwww

In this day and age, different-sized sticks are much less of an issue, if I'm understanding things correctly. You should definitely have the same speed, and it wouldn't hurt to have the same RAM chip manufacturer (although I am not confident that that matters a lot anymore, either). Computers have come a long way in their ability to handle hardware mismatches like you're proposing, so you'll probably be fine, especially with the benefits of having dual channel.

Mismatching them will almost certainly be fine, and worst case scenario you can use only the new 16gb one, taking out the old one.

Buy two and bin/donate your current stick.

Only issue you will face with mismatched sticks is when you have different frequencies.

If one of the sticks is lower, your pc/laptop will be capped at using that for both sticks. This isn't an issue at a hardware level, but if it's a significant difference you may notice it.

For example: one stick is DDR4-2400 and the other is DDR4-1600 then both sticks will be stuck at DDR4-1600

Also make sure your CPU and motherboard support over 16 GB. Intel's CPUs ending with U are (were?) limited to 16 GB.

I was dealing with same question just two weeks ago. I got one ram of 8gb and another of 16gb with slightly different frequencies and CLs. Works smooth.