Building a new system atm. and I wonder if the Enermax Galaxy 850w PSU (it's about 4/5 years old) will not cause any issues in my build untill i get some more money for a new one, in about 1 or 2 month's time. I will not be overclocking anything yet.
Enermax is a good quality brand; you may be fine for awhile. If you want to overclock, do it slowly a little at a time and see how stable your system is. The other factor is your video card, which you don't list.
Should be fine, like a cars engine, it will have lost a little horsepower of the years, but still have enough to power your pc, as long as all the voltages and amps are constant and not wildly fluctuation.
I forgot about it and then i couldn't edit the thread. It's a GeForce 9800GT. When i upgrade the GPU to 6870 or the 6950 i will upgrade the PSU, too.
If what you have is the Enermax Galaxy EGX850EWL, with its combined +12 Volt continuous current rating of 68 Amps and with three 6-pin and two 6+2 pin PCI Express supplementary power connectors, there is really no need to replace it when you upgrade your graphics card to a Radeon HD 6870 or a Radeon HD 6950.
It already has the 24-pin ATX main power connector and 8-pin ATX 12V power connector required by the GIGABYTE GA-P67A-UD4-B3 motherboard.
Sure. Check the current voltage readings in the bios or at the first post screen with your new motherboard in the hardware monitor section. The allowance is +/- .5%. So the 12v reading can be between 11.7 and 12.5 (approximately) and should be fairly steady.