2nd PSU for VGA

[Roberto72]

My system:
Asus A7V600 mobo
Athlon 2500 xp-m (14*133mHz default)
2*512mb
X800SE (AGP) (425/400 default)
2*80Gb IBM's
DVD-ROM
DVD-RW
3*120mm fan's
300W HEC psu

I overclock the CPU and VGA. CPU is running @ 12*200 (2400mHz) and VGA @ 500/500. With this setup it is running stable.
If I calculate the needed power for this system (calc systems found on the net) I end up around 300 - 320 W so I'm maxing out my PSU right now. I would like to try to ad a second PSU to power the harddisks, DVD's, fan's and the VGA (external power connector) to offload the main PSU.
My question is:
Can I use a different power source for the VGA without damaging the card or mobo?. I know the VGA uses a bit from it's needed power from the AGP slot, but the main part is comming from the external connector

[giorgos th.]

buy another more serious psu to do your job correctly.the best solution is to buy a psu with dual 12v rails.i bought the Enermax liberty and i`m very happy with it.and it is modular.

[Roberto72]

Problem is dual rail won't help me. Mobo has only a 20 pin's (no 24 pin's) atx connector, no extra 4 pin 12V. And even the new PSU's with dual 12v rails still have 30 to 35A on the 5V rail. It is this rail I'm concerned about. Also why buy an expensive 400 or 500 W psu when I have 3 300W psu's laying around?

[W1zzard]

do you actually have problems caused by your psu?

[Roberto72]

do you actually have problems caused by your psu?
No, system is stable, no BSOD or freezes.
A few months ago a upgraded my VGA from a GF4ti200 to a X800SE. After this upgrade I could overclock my CPU from 11.5*200 to 12*200. The X800SE is powered not thru the AGP slot but by an external power connector so it looks like the mobo had problems with power drain via the AGP slot and this affected also the CPU. What I would like to accomplish is to unload the main PSU in order to get a higher overclock on CPU and VGA