Question Odd freezings. Suspect graphic card.

[exocet2647]

Hi! Noob here. I have random freezings with my computer and I'm trying to check any component.
Looking at the graphic card (Shappire R9 280X), I see in the specs it needs 750W (https://www.cnet.com/products/sapphire-radeon-r9-280x-dual-x-oc-graphics-card-radeon-r9-280x-3-gb/).

¿Does that means 750W power supply or 750W only for the graphic card at maximun? Because who built my computer installed a 750W power supply...

Note: Freezing totally. You need to unplug and plug again. No alert or error screen in any way.
Note2: Checked every component and peripheric except for the graphic card, motherboard and micro.

Thank you in advance.

Update:

Built in 2014, Windows 10 PRO

AMD FX Series FX-9590 4.7Ghz 8X
Sapphire R9 280X Tri-X UEFI 3GB GDDR5
Crucial M500 240GB SSD SATA3
Gigabyte GA-990FXA-UD3 Rev 4.0
Nox Urano VX 750W PFC
Enermax Liqtech 120X
2x Kingston HyperX Savage DDR3 1866 PC3-14900 8GB CL9

 

[kastriot]

Can you check another psu so you can eliminate it from usual suspect?

 

[exocet2647]

Can you check another psu so you can eliminate it from usual suspect?

I can't without buying another one.
Don't know if the local repair stores have any checking service, but I'll ask.

 

[SamMaster]

750w is more to make sure you have enough headroom for the rest of the system. You would probably be able to get away with a 500/550w power supply, unless you have a lot of peripherals attached to your PC, and are overclocking everything top their limits. It also accounts for crappy PSUs that do not provide their rated power.

 

[exocet2647]

750w is more to make sure you have enough headroom for the rest of the system. You would probably be able to get away with a 500/550w power supply, unless you have a lot of peripherals attached to your PC, and are overclocking everything top their limits. It also accounts for crappy PSUs that do not provide their rated power.

Updated post with system specs.

It worked well a good time but after a while (maybe months, don't remember) it started to crash. Probably something with the heat, since It occurs more often in summer (a lot more). I supposed something with the PSU because with the temperature maybe need some extra for the fans... But maybe is just a damaged micropocessor... I'm lost, only clue is the temperature but appears to be really random. Sometimes many hours without crashes, sometimes crashes every 5min...

Just to clarify: Freezes absolutely, image still without power cut. No sound, no keyboard exit, no error or crash screen. Only way is to keep the power button to restart or unplug.

 

[Shmee]

That sounds like CPU or memory. Have you run memtest86 or ran a CPU stress test?

 

[exocet2647]

That sounds like CPU or memory. Have you run memtest86 or ran a CPU stress test?

I don't know about those things but I'm googlin it and give a try after work.

I have only checked RAM and SSD (both new ones from the store, problem persist).

 

[VirtualLarry]

Mobo VRMs are shot. Get a new, decent, AM3+ mobo.