R9 280X Crashing/Artifacting (NEED HELP)

[headlock_master]

So recently i got 2 R9 280Xs (not new), one is the GV-R928XOC-3GD (rev 3.0) from Gigabyte and the other is the XFX Black Edtion. Both of them look like new.
I installed the XFX one on my PC first, installed the drivers and runned games like GTA V, WWE 2K17, Skyrim, Spore, Rust, GTA IV and Chivalry Medieval Warfare with no problems aside from some almost unnoticeable minor artifacts for like 2 days or more, until one day it suddenly began artifacting a lot while i was playing, and some very strange lines began showing on my screen, like on this video: https://www.youtube.com/watch?v=3nGzGA20f5g (skip to 0:35).
I switched to the Gigabyte one and got the EXACT same problems (wich made me believe it wasn't a problem on the GPUs). It was annoying AF but i still could play, like it could crash in 5 minutes of gameplay or i could play several straight hours without a single artifact. But yesterday, i started up WWE 2K18 and soon when i started a match it would crash violently, sometimes leaving me no choice but to take out the pc and restart. Here's a screenshot of what it showed right after the crash

And now i can't play for 5 minutes straight without crashing or artifacting. I tried underclocking it, downloading old drivers, updating the BIOS, turning the fan speed to 100% but nothing could permanently solve my problem. I didn't witness any crashing or those malefic lines that appears on the screen on any other games aside from WWE 2K18 and 2K17, but on games like Chivalry, Paladins and Mortal Kombat X there were some minor artifacts, like showed in these screenshots (Chivalry):

Less than 1 year ago i was using a GTX 770 that wasn't new too and didn't notice anything like these errors. So i ask you guys, what could my problem possibly be? my system specs are:
Motherboard: Gigabyte GA-B75M-D3H
RAM: 2x4GB Corsair Vengenace
PSU: Corsair TX750
Processor: i5 3330
The SO is on a Kingston 120gb SSD
GPUs: Gigabyte R9 280x GV-R928XOC-3GD and XFX R9 280x Black Edition
Thanks in advance and sorry if the text was sh1t i'm not used to forums (and sorry for my english too, it's not my main language)

 

[headlock_master]

i don't know why the screenshots i linked aren't showing up

 

[Karadjgne]

You have to use a 3rd party host site to upload pictures, it's a security issue to prevent malicious software like viruses and malware from also uploading. Popular sites are imgur and postimages.org

There's 2 main causes of artifacts, the first being funky drivers, which was not uncommon with the 200 series amd gpus.

The second is overheated vram. This is harder to diagnose since the temp sensor is only in the processor, not in the other side which includes the voltage regulatory circuitry and vram. There's several causes of overheating vram which can include serious abuse from crypto-mining, the cards might have had alternative cooling like water blocks and the heatsink recently put back on without sufficient thermal pad/tape on the componentry, high heat usage deterioration of the thermal tape/pad over time, or something as simple as the heatsink under the shroud is really dirty but you can't see it.

If you have redone the drivers (use Driver Deleter Utility (DDU) from guru3d.com) and since the cards are no longer covered by any warranty of any sort, and you now own them outright (doubt you can get a refund on the auction) there's only 1 option left. Tear down. Replace the paste and thermal pad/tape

 

[WiiUMasterGman]

Also if you overclock you could be artifacting

 

[headlock_master]

I installed many old drivers and got the exact same problems with every one of them, and i really don't think they were used for mining. I didn't overclock any of them.
And yeah they can be overheating, the last time i checked it got 65ºC+ (the Gigabyte one) on Skyrim, the XFX one got 40Cº+ on idling, and i didn't check the temps but the card got really hot while i was playing WWE 2K18, when it crashed.

 

[R0GG]

I am suspecting either:
- INSUFFICIENT POWER DELIVERY: can be avoided by having the graphic card 2 PCIe Power connectors coming from 2 different Power Supply PCIe cables (fixed my artifacting PowerColor R9 280x few years ago despite renown PSU Seasonic X850 Gold).
- INNER GRAPHICS COMPONENTS OVERHEATING: solution:Increasing your computer case overall airflow and in the immediate proximity of the card : I run a R9 290X in all year round open case and when gaming I have to ramp up all cases fans speeds especially those placed under and above the card by the drives cage sending air streams horizontally under the card (helping card fans) an above card (help cooling PCB and motherboard northbridge ++[ which you could monitor temps using Hwinfo]): otherwise the card would start artifacting even at stock clocks and within specifications temperatures : this fixed my R9 290x incline to artifact for good.