Grahpics Card Decision Help

allahpayneyo

Honorable
Mar 29, 2013
76
0
10,630
Need some advice from you guys.
Current Situation:
I currently have an InWin D-Frame Mini case with an i7-4790k, 8GB of ram, and a GTX 970 MSI 4g. The CPU is cooled by an H100i GTX AIO cooler from Corsair. The only fans in the case are the two fans connected to the cpu cooler, as the case (if you do not know the model) is an open air model, and does not have slots for fans.
Upgrade path:
I decided that after about a year of building pcs on my own and the experience that comes with building the 3 computers I have now I should try to make an attempt in water cooling. I've always wanted to do it, but I've never actually had a really good opportunity to learn all the aspects of it and just kept on sticking with air cooling with a cpu aio cooler.
But, about a month ago the EK-KIT D240 (In Win D-Frame Mini drop-in) was released and had my attention. I've never really looked into water cooling too much, but with the release of this kit and the lower level of experience needed to actually install the kit, I was sold. So, I bought it. Then I decided that I'd need a waterblock for my 970, but then got side tracked in that I decided to sli that msi 970 with my other one already installed in my X99 build.
So, I started shopping for graphics cards, and having owned the GTX 980 Matrix Platinums in SLI in my other rig, thought that the Asus Poseidon series was the way to go. I was planning on buying the 980, but then the 780 was listed by an Amazon seller for around 350 and I jumped and bought it. I will be running this rig on the Acer GN246HL 144Hz monitor. I looked into the frames that this card could put out, and in my research I found there are people out there who find frame stuttering just running on 60Hz, so now I'm worried.
The 780 Poseidon is in like new condition, with no visible scratches and the previous owner only had it for a few weeks. Should I keep the 780 and just try it out in my rig and risk the chance it's not good enough after I install my water cooling loop and use the card which might mean a 20% restocking fee, or do I just give in, return the 780 and buy the 980 posiedon off of amazon and just install that in my rig knowing it will push out enough frames. The only game I will be running on this computer (as it is actually my work computer at home) is Counter Strike Global Offensive. I have 2 other sets of triple monitors I game / occasionally work on for different occassions, with one set of IPS Acer H236HL for non-FPS games and other projects that need good colors, and then the other set which is BenQ RL2455HMs for shooters/fast action games and heavy video editing.
TL;DR Installing first custom loop soon. Do I risk the chance of the GTX 780 Poseidon not being able to push out good 144Hz video in CS:GO Mid-High Settings 1600:900 after installing the loop and putting everything together, or do I just go with the safe and more expensive route of picking up the GTX 980 Poseidon (or a different water cooled card w/ custom block) which I know will do the heavy loading required? Or, of course, am I in fact heading in the complete wrong direction?