Please help: New PSU either does no display or does not boot

[Jezza_]

I recently installed a new Corsair Builder Series CXM 600W. At first, all fans started to spin (really quickly and loudly though) and lights and Hard drives turned on. However there was no display on any monitor. Then having unplugged many things, the computer would not even boot or boot for a tiny second then turn off. I got a replacement unit off amazon so I don't think the unit was broken as the replacement has the same issue. When I plug in my old PSU (http://www.amazon.co.uk/CiT-450W-Silent-Power-Supply/dp/B0064A14VE/ref=sr_1_fkmr1_2?ie=UTF8&qid=1447081923&sr=8-2-fkmr1&keywords=gold+psu+cit+550), the PC boots and starts fine. So what is wrong?! Is it a compatibility issue or something? Am I not plugging in the right things? I would REALLY appreciate any help. Thank you.

Specs:
MOBO: z77 ds3h
GPU: GTX 650ti
Processor: i5 Ivy Bridge
PSU: Corsair CXM 600W

 

[Hawkshot]

Get a refund for the PSU, they are known for being terrible quality and it seems to be faulty anyway, just get rid of it.

 

[Jezza_]

Get a refund for the PSU, they are known for being terrible quality and it seems to be faulty anyway, just get rid of it.

Ok. It does sound faulty but it is strange that even the replacement didn't work. Do you have a suggestion for a PSU that I can get?

 

[Hawkshot]

of course, look at anything from XFX these are amazing built PSU alternatively you can look at EVGA G2 series as these are top of the range but not overly expensive either.

 

[Jezza_]

of course, look at anything from XFX these are amazing built PSU alternatively you can look at EVGA G2 series as these are top of the range but not overly expensive either.

Cheers. Turns out there is a fault with these PSU's seemingly that there is a minimum amount of power for it to turn on. Had to plug in some fans, GPU and hard drives.

However, still cannot get display from computer. Tried both a GTX 970 and a GTX 650ti. Any ideas man? Could it still be the power supply?

 

[Hawkshot]

I suppose it is the most likely cause as you have already tried 2 different GPU's the only other things it could be is the screen itself or Mobo problem, do you get any beep codes when you turn on the computer?

 

[Vic 40]

Tried the igp as well?