Standard Elvui which is fine, but it EATS memory and I just want my frame rate to be steadier on these fights. IT hangs around 50-120 but jumps wildly. With elvui off (again, it's a resource hog and not efficient) it'll be steady at 120+ on ultra.
I want the Elvui raid frames, and that's it. And preferably whatever all goes into how it shows dispels/debuffs as well. I LOVE them. I just don't really need anything else =/
Memory has essentially nothing to do with frame rates. The only way memory use could hurt frame rates is if you were running out, and...if 1 *megabyte* is making a noticeable impact on your free memory, you should probably upgrade those 128MB SDRAM SIMMs you're using.
The main way addons have a performance impact is through CPU time. In ElvUI, the raid frames are probably the biggest contributor to CPU use in combat, sad to say. Most of the rest of the UI isn't really doing anything in combat but sitting there looking pretty. Raid frames, boss mods, scrolling combat text, nameplates, and meters are the major CPU offender
You might try turning off the SCT and nameplates. That might help.
If you dont have a 120hz monitor, though, try capping the framerate at 60. I use a tool that came with my motherboard, but your graphics card drivers can probably do it too. Your monitor can't display more than 60, so capping it should give you the consistency you want.