When you start games, the computer goes into reboot, what could be the reason?

Question

Iron

For a week now, my system has gone into a reboot as soon as I start the games, any, 5 seconds and the computer restarts. I cleaned it from dust, changed the thermal paste, updated the drivers for the video card, even demolished the system, switched from 7 to 10 at home, nothing helped. And here's what's interesting, I insert an old 2 GB video card, everything works well, games do not crash, I insert my GeForce "GTX 970 GAMING 4G", and again the same problem. I don't know what to think, is it the graphics card? Or the power supply has failed and cannot withstand the load, because the old one consumes less energy. And sometimes, when I reboot, it throws me into the BIOS and I can’t exit it, I have to turn off the computer from the network and reboot again, then everything is fine. I also noticed that sometimes when you reboot, the sound of the game remains, the system unit is turned on, and the screen goes out and does not turn on. And sometimes everything works fine at all, it doesn’t go into a reboot, but this is very rare. I do not know what to think, I hope for your help.
Here are the data and components of my PC:
1) ASUS Socket-AM3+M5A97 AMD970/SB950 4xDDR3-2133 2xPCI-E(16+4) 8ch 6xSATA3 RAID 2xUSB3 GLAN ATX board
2) AMD FX-8320 3.5GHz (Turbo up to 4.0) GHz) 16Mb DDR3-1866 Socket-AM3+ OEM
3) Memory DIMM DDR3 4096MB PC12800 1600MHz Samsung orig.
4) SATA-3 1Tb Seagate 7200 Barracuda [ST1000DM003] Cache 64MB
5) PCI-E MSI GeForce GTX 970 GAMING 4G 4096MB 256bit GDDR5 [GTX 970 GAMING 4G] DVI HDMI DisplayPort
6) SATA DVD-RW Pioneer (DVR) -219LBK/S19LBK/220LBK) Black DVD-24x/8x/16x. DL-12x, CD-40x/32x/40x "LF"
7) PSU ATX FinePower DNP-550 500W+power cord 1.5m
8) Case Miditower ATX ZALMAN Z9 U3 Without PSU
9) Cooler IceHammer IH-3080WV (Al, 2200rpm, 42.7 CFM, 20dBA) Socket 775/1150/1155/1156/AM2/AM2+/AM3/AM3+/FM1
10) Monitor LG 23"23EA53T [IPS, LED, 1920x1080, 5M :1, 6ms, 178hor/178ver, D-Sub, DVI]

Answer 1

90% of all cases of freezing, rebooting and not turning on the computer due to the power supply
further due to overheating
and only then
change the power supply due to other pieces of iron

Answer 2

Some kind of crap to try to power the GTX 970 (145W according to the passport), FX-8320 (125W according to the passport) and other small things for the declared 370W?
You are a risk taker.

Answer 3

Thank you for your help. Unfortunately in my city in DNS there was not a rich choice of power supplies, I took the best that they had - "kcas 700w 80 plus bronze". The problem immediately disappeared and does not bother to this day.

Answer 4

Take PSU Seasonic for 750W platinum and you will be happy.

Answer 5

Undoubtedly a weak power supply, calculate what kind of PSU you need for your configuration here:
outervision.com/power-supply-calculator
but of course it will give a result with a margin

Answer 6

look at operating fee