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.

But i7-6700 TDP is only 65W, almost 1/3 of 970 right? I managed to dota on second lowest settings for an hour without any issues. Gonna try ASUS RealBench now.

Most probably your PC is dusty. You should clean up the dusts in the fan of your desktop. I used tohave the same problem, but that was after a few minutes of gaming.. Lol. Once i cleaned the fans then no problem till this day.. But just to make sure, try cleaning it first, unless youre using a water cooler. The other option is to check the temps of your cpu and gpu. I dont think your psu would be causing the problem. Corsair PSUs are in good rating. im using a corsair one too. No problem whatsoever. haha.

Your PSU should be more than enough to support.. Lol. 970 is about 90W your i7 also maybe at most 125W. lol.

Can I know what GPU u using at that time?

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.

I've tried re-run prime95 together with unigine heaven and it instantly crashed. Run at FHD with ultra settings will have instant crash as well lol.

Actually after reading feedbacks here and digging around..maybe it's PSU problem so gonna try that first. I've just ordered super flower leadex 750W and see if it works.

Thanks a lot btw!   

The same GPU I'm using now, GTX970 msi gaming. I switched to a new PSU then no more problem already.

Meantime, you can try setting the Power Limit % in MSI afterburner to 60-70%. Gigabyte's GTX970 has a modified power limit of 250W (means the board can draw up to 250W). Setting it to 60% will limit it to ~150W draw (which is the same as stock GTX970).

oh I'm using Gigabyte, they call it Gigabyte OC guru. So reducing clock speed or set power target?

my win10 usually Alt-Tab out when gaming.. annoying

I've tried re-run prime95 together with unigine heaven and it instantly crashed. Run at FHD with ultra settings will have instant crash as well lol.

your keyboard key stuck is it?

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.

When I say your reply I need to double check to see if I posted in /k

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

And why did you buy a GTX 970?

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.