(A lot) more RAM at (slightly) slower clock speed, or vice versa?

[dannymcgee]

Recently I've noticed my PC's performance slowing down, with near 100% memory usage, so I decided to go ahead and upgrade my RAM. Previously, I'd had 12 GB installed (8 GB carried over from my last machine + 4 GB that I had added on more recently). But because that 8 GB came from my last machine, it wasn't quite running at the max speed this motherboard allows for. I've now bought 16 GB of RAM that's actually the right speed for my CPU/motherboard (1866 MHz). What I'm wondering is if I should outright replace the old 12 GB with the new 16 GB, for a slight capacity upgrade plus a slight speed boost, or if I should add the new 16 GB to the old 8 GB, for a total of 24 GB of RAM, running at the slightly slower 1600 MHz clock speed?

TL;DR: 24 GB @ 1600 MHz vs. 16 GB @ 1866 MHz — which will give me the biggest overall performance boost?

For what it's worth, I'm a graphic designer, web developer, and a gamer. I frequently run with dozens of Chrome tabs open + my IDE + Photoshop + Illustrator, with large documents open. It's not uncommon to see Photoshop taking up a couple of gigs of memory all by itself. I also play some really demanding games like Planet Coaster.

 

[CountMike]

If choice must be made because of constant high memory usage than quantity beats speed any day. Lower frequency RAM usually has lower latency which practically evens up actual speed of RAM with that much spread in frequency. As for games, above 8GB most probably would not matter.

 

[Sohom]

Use the new 16 gb sticks and dont mix two different ram modules as there maybe incompatibility and even performance issues... Always buy the exact same ram modules while adding extra RAM... Use the 16 GB ram modules