Hello everyone, I'm not really experienced with the computer hardware things (I stopped regularly following this subject around the time multi core cpus started being a thing), but I've always wanted a really nice computer so a couple years back I decided to build one! I understand that every few years you pretty much need a new computer, and I'm feeling like I'm due for an upgrade. I'm just curious what the input is from people who actually know what they're doing. Here's what I've got currently:

CPU - 4790k running 4.4 GhZ (temps are high since I'm running an open air test bench setup, but the looks are worth it)
GPU - 2x MSI R9 290
RAM - 16 GB of Trident 2400 DDR3
Motherboard - MSI gaming 7
HDD - 256GB Samsung 850 Pro w/ 2 TB Barracuda as backup/storage
Monitor - Asus 60 hz 2k monitor (don't remember the model number exactly, Went with higher resolution over refresh rate since I usually play more strategy than twitch games so having more screen real estate is worth more to me than 120 fps)
PSU - EVGA supernova 1200 P2

When I put this together a ton of new tech (DDR 4, new kind of SSD) was just coming out, so I tried to score the best I could of the old generation without paying 3x the cost for marginal performance gains on new stuff, but by now it seems like the new generation of tech is here and at prices that are reasonable. I'm guessing the weakest link here is the GPU, or maybe the monitor. It still runs most stuff I play just fine at ultra quality, but there's some fps hiccups at times. That's why I bought the second GPU, but it seems like crossfire isn't really supported that well. I'm thinking of going to the dark side and buying a Nvidia Ti.

So, any suggestions? A new card I can slot in? Time to just scrap everything and start over?