Run Prime95 and Furmark same time.

If CPU, GPU and PSU all no problem it won't breakdown.

You might want to try gaming this time but with only 1 stick of RAM, see if it happens.

Go Leadex la, good brand. Seasonic also good actually. All depends on model.

You ran Unigine Heaven 720p for a few minutes and it rebooted.

You ran Furmark confirm sure reboot.

From the above, I'd say it's GPU problem rather than PSU problem.

You see, i7 6700 on Prime95 would've loaded the PSU quite a fair bit. Running Furmark would load it a lot more (from GPU) - higher wattage drawn and if there's an issue here it might be because it draws more power than your PSU can supply (happens on old PSU)

but you said your system is new, so given the above that you run Unigine Heaven at 720P for a few minutes and it reboot, it could be the GPU having problem.

I think another thing you can try running is 3Dmark, try out other games too.

Try out ASUS RealBench as well. https://rog.asus.com/tag/realbench/

If ASUS Realbench pass and Prime95 no issue but running games and graphics benchmark results in reboot, I'd point it to GPU first.

If your PSU cacat, what voltage also may cause problem.

GTX 970 typically draws around 170-180W, higher than the 145W on Nvidia specs sheet.

I have the VS550 and it last ages and it shouldn't have problem handling your PC load but being an entry level PSU, do consider upgrading it for better protection.

However in this case we have to go into greater detail, just in case you change PSU already and problem still persists.

I think one good way to determine is you take note at which part Unigine Heaven crashes. Run at Full HD (you have FHD monitor?) at 8xAA, Ultra settings and what not set to max.

Dust accumulate causes heat build up, not reboots.

970 is 145w on specs, typical 970 draws 170 - 180w range.

i7 varies but typically i7 draws under 100W but even so they don't draw their rated TDP wattage all the time.

Processor power draw is subjected to load.

OK so based on your latest post, it's most likely the PSU.

Too bad my VS550 already KO if not I can test it to see whether same result.

Shop give you old stock ah?

And no, don't need to do the power target thing. You lower power target it also will run at lower performance.

Actually senang case just bring it back to them see how they settle for you.

And why did you buy a GTX 970?

970 is old, but hope you got it at a good price under RM 1,000.

Shutdown is correct. Not reboot. Our systems will power down when overheat.

Eh when 1070 / 1080 were released the 970 price dropped below 1000 already.

Nmind la, LYN forum is a good place to consult next time.