GPU or PSU

[gogi]

So im in the process of getting a better PSU (chieftec a80 750W, had corsair VS 650W) to see if my boot problem will be fixed
After getting a new GPU asus r9 280x which may very much be faulty since i bought it second hand, although other than the boot problem the GPU when i boot up works without a problem or a hiccup, perfect temperature perfect stability (did stress tests).
The thing is as i stated before the system wont boot sometimes, it does turn on but no keyboard no mouse no monitor and not even HDD indicator comes up.(and sometimes everything boots up and works fine with no crashing)
Anyone with any ideas for a fix....I really do hope the new PSU resolves this problem.
Build: AMD fx 8120
Mobo: asrock 970 extreme3
Ram 8gb dual channel
Also i have around 7 fans on my case including leds

 

[crisan_tiberiu]

have you tried a BIOS update for the motherboard? or do you have the latest firmware?

 

[gogi]

I did update it not too long ago, like a month or two back.

 

[4745454b]

I'm not sure that's a better PSU. More stated wattage != better PSU. Knowing chieftec's abilities, it is at best equal to the Corsair which you already have.

That said, from my experience what you are talking about is normally caused by a bad PSU, motherboard, or sometimes RAM. But usually the PSU or board. I wouldn't have gone with that chieftec however. From looking online the A80 is supposedly the CTG-750C. Looking at this database it's made by Sirtec (not good) has only two 8pin PCIe plugs (should have 4) and isn't 80+ certified. I wouldn't have bothered buying that PSU.

http://www.realhardtechx.com/index_archivos/Page873.htm

 

[gogi]

On their site it says its 85% efficient http://www.chieftec.eu/en/psus/a-80-series/ctg-750c.html
Much like my corsair..