SuperCuber

high end desktop

High-End Desktop.
CPUs on sockets such as LGA 2066 (for intel) and TR4 (for AMD).
 

High End DeskTop Afaik not to sure if theres any other meaning to dt

The part of the system that interfaces with the memory (which is on the CPU), only supports dual channel.
Only threadripper and Intel HEDT CPUs (as well as most server class gear) support quad channel memory.

The platform is limited to dual channel only HEDT platforms have quad channel iirc

Z270 can't do quad channel, only two sets of dual channel (assuming it has 4 memory slots).

z270 (AKA LGA 1151, consumer platform) doesn't support quad channel, only dual.
U need to with a HEDT platform to get quad channel.

Apparently RAM can make a big difference in GTA 5, so an upgrade would be noticeable there. 

You said 15+ fps gains would be worth it: 
Looks like 15-30fps gains depending on what's going on, so defo a worthwhile upgrade. 3200Mhz would be a slight boost over 3000, and it's usually the same price or like $2 more so I'd go with that. 

Should be able to find comparison videos like this for the other games if you search around. 

Stuff like GTA5, Borderlands, Dying Light, Battlefield, CoD, Metro..
 
All right. Thanks again!!

What games are you playing? You'll get 10-30 point gains in a Cinebench R20 run with faster RAM, that's about it. Outside of synthetic benches it depends on the game. 

If you have the budget for it I'd just get a 2x8GB or 2x16GB kit of 3200Mhz CL16 or 3000Mhz CL15 stuff and call it a day, that's the sweet spot for performance on most platforms and you won't need to worry about your RAM bottlenecking you in games. 

 

Right, basically exactly what I said but he used more of those letter things
 
Now, are you SURE they are 2133MHz sticks, or is that what software or Windows is reporting?  They may be faster and you need to put XMP on.

Thank you, that makes totally sense! 

Ryzen's infinity fabric depends (depended? apparently Zen 2 is a bit different) on RAM speeds or something, higher clocked RAM gives the CPU a boost as well. 

On Intel the CPU really doesn't care, it's on an app to app, game to game basis. Apparently Fallout 4, 76, and other games that stream stuff from the RAM get a massive boost with faster DIMMs, games that don't really care won't see an improvement. 
 
^^^ Always go for half the DIMM count you can fit. Both to leave room for future upgrades if you need more RAM in future, and to let your RAM clock higher, easier. More DIMMs puts more stress on your IPC, if you decide to manually tweak your RAM you probably won't be able to push 4 DIMMs as far as 2. 

On HEDT you'd go for a 4x kit (like I have) because they support quad channel (or triple channel on X58, hexa channel on the newest Intel Xeon based platforms), consumer stuff only runs dual channel. 4 sticks won't be any faster than 2 so there's no reason to put the stress on your IPC unless you need a large amount of RAM. Up to 32GB you can do on 2 DIMMs, above that you need to go to 4x (I know there's 32GB DIMMs but I think they're all server stuff). 

Your motherboard supports 4 sticks, but uses them in dual channel mode.  It's mostly just HEDT systems that do quad channel.