I also said the 2x times the cost of the 5700 xt for a card that would crash is not worth it. The driver read me list that as a issue and black screen sometimes.
Nope it could be the card. its done it since day one, The one in the system for 60 days before the 5700 xt was a AMD card (R9 390X) and it worked fine.
The 5700 XT run fast it just crashes. it only crashed one time tonight.
I had the EXACT same problem as you with my XFX RX 6800 XT Triple-Dissipation model (what a mouthful). Initially, it was fine for a bit and then it started crashing badly. We're talking green-screen, buzzing sound and full system reset. It was even doing this in older games like Bioshock Infinite and Dragon Age: Inquisition.
I tried changing the drivers 4 times with DDU and while they could slightly change the behaviour of the crashes (black screen instead of green for instance), they couldn't stop them from happening.
I sent my card in for an RMA because I had given up (something that I had never done before). I've been servicing my own computers since the 80s so if I couldn't fix it, there had to be something wrong with the card itself. XFX asked me to do a couple of things (which I did) but one of the things was to verify that my PSU was good. I wasn't about to take my entire system apart so what I did was I took my 5700 XT out and replaced it with one of my Sapphire R9 Fury Nitro OC+ cards.
Now, the RX 5700 XT's TDP is 225W while the R9 Fury's TDP is 275W. I TRIED to make the R9 Fury crash. I didn't change drivers, I tabbed in and out of games, ran it at 4K medium, etc. I could not get that card to crash and my PSU is an EVGA 1000 G2 Supernova (1kW, 80+Gold) so I knew that wasn't the problem and told them so. To their credit, they readily agreed that the PSU was clearly not the issue.
They said that they couldn't get the card to crash in benchmarks (It never crashed in benchmarks for me either) but never actually tested it in games. They said "to be safe, we'll replace your card" to which I said "that's all I want". Well, XFX's fantastic customer service is clearly still intact from when I bought my two HD 4870s because they replaced my card with a THICC III (no complaints here)! When I was installing it, I was surprised to discover that it had 2 x 8-pin PCI-E connectors instead of the 1 x 8 and 1 x 6 on the Triple Dissipation. I thought that was odd but thought "whatever" and installed it.
Well, the difference was night and day. I've had it for about a week now and ZERO CRASHES on ANYTHING. I didn't even use DDU or anything because I wanted to see if it would crash again. It's as solid as my R9 Furies.
I wondered if the original card was defective because I'd never seen driver problems that could cause such violent hardware crashes (I have seen automotive drivers cause violent crashes though...lol). However, after a bit of research I learned that the crashes I experienced were similar to that of a weak PSU despite the fact that I obviously don't have a weak PSU. Video cards crash hard and violently when they're improperly fed so that's interesting...
Now, since reviewers tend to review cards that get sent to them, they would have reviewed the reference cards from ATi and only high-end AIB models. Just try to find an online review for the XFX Triple-Dissipation 5700 XT, you won't. Try to find a review for the THICC III, you won't. All you'll find is the THICC III Ultra because that's the highest-end model.
Now, ATi would have been very meticulous about the power connectors on their cards but what if the AIBs weren't? What if there was a defect in a batch of 6-pin PCI-E female connectors? These are sold in lots of 20,000 or so and it's probably the same supplier for several of the Radeon AIB cards.
The other possibility is that the 8+6 is sufficient for a blower or twin-fan cooling solution but just barely insufficient for a triple-fan solution (I'm just spit-balling here). I do think that this explains why people can't figure out what's causing the crashes because who would look at the power connectors like that? I sure wouldn't, but I am experienced enough to notice the new configuration and the complete lack of any issues thereafter.
RMA your card and ask for a model with two 8-pin connectors. If you can get it, I think that will solve every problem that you've ever had with the card.