After a bit of research I found out that you have to look at your motherboard documents!

Motherboards only accept certain types of RAM chips, the ones it works with will be stated in the documentation. I would recommend checking model number on the board and searching online if the documents have been lost.

If you get any different then the recommended type it may work ok to the reduced clocking speed, or just not work at all. I’d recommend checking the documentation. Sorry!

Also – if you gambled and upgraded the size without consulting manual it could be the case that the motherboard could not take it. Older boards have a low limit so the max they can take is around 2GB. If you was to upgrade to higher then it could take it would only see maximum it could take.

E.g it can take 2gb, (2x1gbs) you put it 4gb, it would either only see 1gb of each or none at all.

Hope that helps!