I have yet to see a game that requires a certain type of memory, its almost always just a certain amount.
Are there are any that require ddr4 now?
The amount might in a way suggest it has to be DDR4 as there is probably a max size dimm for each generation. I can't seem to find a table that shows it all
Only ddr3 I can find that is 128gb is a set of 8 sticks. 32gb is 2 x 16gb sticks. Max dimm size is 16gb. I think some ddr3 mb had 8 slots but most only had 4 so most ram is likely 64gb. I don't know if thats a board limit though. More a physical one.
Where the next split is between DDR4 & 5, I don't know. Its still reliant on CPU/MB supporting more I think. I suspect the CPU controller is what is restricting how much is on boards. Right now, max dimm size is basically stuck at the max amount of ram you can use on the motherboard.
All the new ones (apart from Threadripper and super silly high end) max out at 128gb of ram.
You can get 128gb dimms of DDR4 & DDR5 so we have to wait until the Motherboard limit is raised before you may see the dividing line between both.
And games that require 128gb or more of ram won't happen any time soon. Majority of PC only have 16gb or less now. While I see a lot of new PC with 64gb of ram on Tom's Hardware, those are just the outliers of the crowd who always buy the next generation of hardware.
The majority are way behind
So game demands are likely to see a base of 16gb for a while to come. Recommended might creep higher but most people don't have top end PC's. You catering to a small percentage of your players who are all impressed by shiny graphics.
We used to get people asking questions in the laptop area who thought their potatoes were still high end.
Meanwhile, in another universe...
My new GPU has 20gb of vram
My PC only has 32gb of ram
shared amount of ram would be 16gb
Its really good that the shared amount is only taken if needed as it would suck if everytime you added ram, the PC gave half of it to the GPU, and I wouldn't need a GPU with 36gb of ram
Needing lots of ram to play games is a waste unless you can find other uses for it besides gaming.