Help/Opinion: CrossFire a slightly older card or new GPU

I currently have a Gigabyte R9 280X GDDR5-3GB but on a motherboard that only has one PCIE 16x. I'm contemplating getting a new MB with at least two PCIE 16x slots and grabbing another Gigabyte R9 280X GDDR5-3GB and crossfire them.

My question is would I be better off with the crossfired GPUs or should I simply just grab one Sapphire Radeon NITRO R9 390 8GB GDDR5 and use my old R9 280x in a Steam Machine?

My main concern would be performance of my main PC. My goal is to pull 100+ fps for any game released in the next 2-3 years.

Thanks in advance.

eh I would grab the 390. Crossfire is good. but not always great. there is a bunch of headaches that come with Crossfire. Screen tearing and or graphical issues..

If you are not gaming at 4K i wouldn't recommend the crossfire setup. 1080p and 1440p i would definitely stick with the 290. preferably the Gigabyte G1 Model and or Sapphire Nitro Model

1 strong gpu > 2 medium tiered gpu's. Less driver issues (especially with xfire & windows 10), less power consumption (depends on gpu), less heat buildup in the case as well.
PCIE lane speed wise, x16 means very little. Even x8 speed 2.0 provide more than enough bandwidth for high end gpu's.
This is a good read.

Future proofing doesn't really exist for GPUs.

Mostly just save up and buy a single Fury Card over crossfiring or making a minor jump to a 390, also If I'm not mistaken you can crossfire a 390 with a 280x, but the 390 will downclock? not sure on that, you can do a lot of different things with crossfire usually.

Or save up and get a nice 4k Free-sync display, I know Qain plays elite dangerous at 4k on his 280x.

Your monitor is going to last you a lot longer than a GPU, so it's a decent investment.

Thanks for the help/opinions.

I honestly know nothing about freesync technology though I've heard it mentioned around here. I'll have to do some more research.

You gotta really check the display, make sure it's gotten updated firmware or a good enough scaler to minimize the ghosting issue, not sure if it's only a thing on the high refresh rate IPS displays though

freesync/g-sync/adaptive sync currently does not work in CF/SLi.

GPU's will run at their default clocks, cards will not downclock etc. Though with current CF profile in dx11 titles you will only be able to use smallest gpu memory pool. (thus your 390 will be only able to use 3GB of memory) dx12 supposedly will introduce better systems which memory pool can be polled separately for api.

Whoa there, freesync has worked with crossfire since 15.7 in July last I checked (I have dual 390s but cannot personally confirm because I dont have a freesync monitor), and there is a problem with varying clock speeds but its only when using freesync in crossfire WITH frame rate target control (in list of known issues on AMD's beta release notes).

not that i was aware of it, as far as i know it it doesn't work with cf/sli configs. But if it does already then thats cool.

I just don't think it works very well, dunno how G-sync is doing on that end

I upgraded from 2 of the exact same card you have, just one 390 has slightly less FPS but much smoother/consistent performance as two 280Xs, I just got the 2nd 390 and now run latest titles at 1440p max settings (except AA) but most older games I use VSR to downsample 3200x1800 with ultra settings and stiil dont drop under 60fps.

googled it:
Gsync and SLI not smooth. Stuttering and not consistently smooth

guess that answer that question.

After reading about it, Gsync / Freesync sound amazing. I'll probably end up sticking with AMD / Freesync to do my part to encourage competition, but whoa I don't know how I'm going to break it to the wife that now I need a new monitor...

Might as well spring for that 4k monitor if you're going to get anything