Question I've had a problem for weeks that won't go away, help!

[PivotLies]

So around the end of march I started having an issue on my pc that at first only affected games, but then spread to even videos or even just browsing it seems. Before that my computer ran completely fine.

All of my video will "hitch" every few minutes about 2-5 times in a row, audio keeps playing normally but applications freeze for a moment and catch up about half a second later. It doesn't happen all the time, but when stressed it will.

I have a friend that does computer work for a living, so I spent about 4 days going over my pc with them and what could be wrong to no avail.

The fixes we tried were:
•Downloaded latest drivers for Windows, Graphics card, and mother board
•removed all graphics drivers from computer and did a fresh install
•Opened and cleaned computer, moved ram sticks into better(?) position
•rolled back windows version to previous release

Other noted problems:
•My ram situation is a little odd, I wanted 2 8gb sticks but could only afford the one for now, so I currently have 2 very old sticks of ram, and 1 new one. the 2 old ones are in positions 2 and 4, the new stick is in position 3 right between them
•The gpu itself sags pretty significantly, having nothing to prop it up on the other side that'd be safe inside my computer (told I shouldn't use a rubber band). Yet when I did prop it back up, the fans started working beyond overtime when I'd start a game, checking Speccy it told me my gpu was at a staggering 90C. Immediately stopped the game and removed the prop, started it back up again and the game ran at a normal temp again.

Specs: Summary
Operating System
Windows 10 Home 64-bit
CPU
AMD FX-8370 25 °C
Vishera 32nm Technology
RAM
16.0GB Dual-Channel DDR3 @ 669MHz (9-9-9-24)
Motherboard
Gigabyte Technology Co. Ltd. 970A-DS3P FX (CPU 1) 33 °C
Graphics
DELL E2414H (1920x1080@60Hz)
HP 22cwa (1920x1080@60Hz)
4095MB NVIDIA GeForce GTX 970 (ASUStek Computer Inc) 47 °C
Storage
1863GB Seagate ST2000DM006-2DM164 (SATA) 30 °C
Optical Drives
HL-DT-ST DVDRAM GH24NSB0
Audio
Realtek High Definition Audio

 

[g-unit1111]

It's entirely possible that mismatched RAM could be the source of your troubles. Take both sticks out and try running them one at a time in every available RAM slot. If they both work, use the slots where they both work. If only one works, then use that one. If you try that and it still doesn't work then it's possible that your motherboard or power supply could be failing.

 

[PivotLies]

It's entirely possible that mismatched RAM could be the source of your troubles. Take both sticks out and try running them one at a time in every available RAM slot. If they both work, use the slots where they both work. If only one works, then use that one. If you try that and it still doesn't work then it's possible that your motherboard or power supply could be failing.

that doesn't quite explain how this only just started becoming a problem at the end of March, after working fine for years. It could just be the start of it failing but I'd like to rule out every possibility before needing to buy new hardware.
also after reading through the manual for the mother board, it will default to using positions 2 and 4 as the first dual channel slots, then 1 and 3 after it, it's just a question of whether i want the default to be the new ram or the 2 old ones.