Currently browsing for gaming PCs and ran into this one that they'll sell for $300, is it worth it and will it run BeamNG?
Yes, it'll run BeamNG but it won't do it well. The 970 released in 2014 and with the age there may be some problems in the near future, especially if the power supply is just as old. Anyways, before purchasing I would suggest looking for another PC with better specs. It looks like you're not very familiar with computer components so feel free to send anymore you find here within your price range. Don't forget to check your local craigslist for computers too. Edit: By "not well" I'd estimate you'd be able to hit 60FPS on lower graphical settings but it wouldn't be consistent. If you could, find a better deal for a similar price. Overall it's not a horrible deal provided everything functions, try to haggle if you can assuming there are no other options. --- Post updated --- If you really desire frames at a consistent 60fps or higher, assuming that the 970 won't be able to dish out 60fps consistently you could play at a lower resolution or sell the graphics card and use that money towards buying a new one. There are 1660 supers, 980tis, gtx 1070s, rx 590s, etc in my area that are under $100 and with one of those cards you could easily double or nearly double your frames. Consider that if you really value your money like me : )
Thermal performance isnt great, and they wont have nearly as much longevity. I suppose if portability is a must then go for one but desktops are far better choices for this sort of thing if you're staying in one spot.
I personally have one of the worst computers to run BeamNG, but strangely it runs very well in Low setting (and poorly in Lowest because of I don't know). GT 1030, i5-4570, 16GB of DDR3 memory. So the GTX 970 can run BeamNG at Normal settings I think.