1. With those displays you are pushing the limits of the GPU. That 144Hz is more than the load of 2 everyday 1080p 60Hz displays and we know the 980 barely does UHD 4K so right there I say you're pushing the limits.
2. On top of that, it's just an i3 and 8GB RAM. We are right at the point there will be complaints.
3. USB Flash drive. Can cause odd delays. Do not leave it in when max performance is expected.
4. JAVA. If not used, uninstall both. If used, uninstall both and install just one.
5. Power Profile. Set all to no sleep and try a powered profile. Not balanced.
6. http://www.blackviper.com/service-configurations/black-vipers-windows-10-service-configurations/
I see Payments and NFC enabled. Not required for gamers. DISABLE THAT.
7. McAfee. Must be a remnant. Remove with McAfee removal tools.
8. Did you turn off Update Sharing? Always turn that off. Read:
https://www.howtogeek.com/224981/how-to-stop-windows-10-from-uploading-updates-to-other-pcs-over-the-internet/
9. Channels #: Single
Check your motherboard manual to see if you have the RAM in the right slots. You want DUAL for best performance. Can cause hard to pinpoint graphic delays.
10. BIOS is out of date. Because this is a Ryzen I keep the BIOS current.
https://www.asus.com/us/Motherboards/PRIME-B350-PLUS/HelpDesk_BIOS/
11. Drives look to be in perfect condition. Would not suspect an issue here.
12. That ODD (optical disc drive.) Unplug for now.
13. DNS is 192.x.x.x. If you play online, try 8.8.8.8
----> The single channel ram, unplug the USB flash drive and W10 update sharing should be done first. Then test.
Windows 10 64 Home hand built PC (core i3 3220, 8 GB ddr3 RAM, NVIDIA GTX 970, 1TB HDD
http://speccy.piriform.com/results/XqMgtkatuPZHXs8YGkzLpsY
Microstutter started a few months ago, seems to have come back with vengance since last week, whereas it used to be only intensive games (Smite/EUIV/FM) it has now seemingly carried over to ever ounce of my pc. Infrequent as they are, they come in waves. Seemingly causing my pc to freeze for a fraction of a second now and then. Whilst I could do another fresh install I fear i've had this issue before and I'm unsure as to how it can be fixed. I'm not expert and the forums don't help me out much.
If anyone could even just offer a tip I'd be grateful.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic