System slow to boot, weak psu?

[Scania]

I have a core 2 Quad system that always displays the same issue when powering up from an off (as opposed to sleep) state, at power up, the CPU fans spin but I have no output to VGA until I reset (via the reset switch) anything from once to twenty + times, once the system finally posts and boots up, it restarts fine again with no hang no matter how many restarts or resets I do, as soon as I shut down the hang on post returns....?

The system is running a Q8300, 8gb DDR2, Foxconn p45al mobo, GTX260 896 MB, 1 DVD ROM and 1 SATA 500gb HD with an old Antec 650w psu.....

I'm assuming it's a power supply issue? It only happens at power up, The system otherwise runs fine.

Thanks

 

[Scania]

Anybody?

I've pulled my Corsair HX850 from my main rig to try with this one, as suspected, the problem disappears, now it gets interesting, if I put my Coolermaster 550w psu in this rig, it does the same (refuses to post without hitting the reset button a few times) but, putting the Coolermaster psu in my main rig and it posts and boots up just fine (despite being massively overworked by that system)
I'm a bit stumped by this......

 

[Scania]

Does the Antec 650w work for your SLI build?

Yes, having tried the Antec, it powers up and posts fine, but, within a few minutes of launching GTA V the machine powers off , due to overload I assume, even though my Coolermaster 550w psu will run this rig just fine ( I've recently replaced the Coolermaster psu with the Corsair HX850 ) putting the Antec back in the Q8300 system, the refusal to post without many resets returns, as it does with the Coolermaster one too yet both these PSU's will post and boot my SLI build!
I'm fairly sure it's psu related as the problem disappears if I use the Corsair with either build.

I'd have thought either the Antec or Coolermaster would be ample for the Q8300 system, especially given the latter will run my SLI rig albeit way past it's rating!

Just reluctant to have to buy yet another psu, but, want the Q8300 system right, it's for my little boys birthday, I have just over a week to resolve this annoying trait.

 

[Scania]

I've replaced the CMOS battery on both rigs, looks like the Q8300 system is now happy to boot normally with the 550W Coolermaster psu (which is ideal as it's the one I intended to use for this build!) but strangely it's no different with the Antec, which I'm guessing is failing.

I'll stick the Antec in the loft and leave this testing overnight to see if it falls over...

Cheers for the help dacads.