Is My Power Supply Big Enough For A GTX 570

[wiseguy101]

Here are my computer specs:

OCZ 600 Watt StealthXtreme OCZ600SXS
Core 2 Quad Q6600 (G0 stepping)
Asus P5Q-E
2 x 2GB DDR2 1066
Auzentech Prelude sound card
250 GB WD Caviar Blue WD2500AAJS
Geforce GTX570
Samsung sh-203n DVD multi writer
2 x 120mm fans
1 x 90mm fan

I used to have a Geforce 8600 GTS but I am now upgrading to a Geforce GTX 570 GTX (yes I know my Q6600 will most likely be a bottleneck but I can't afford to build a new system right now) and I was wondering if my current power supply will be powerful enough or if I should upgrade it.

I'm pretty sure I have enough wattage, my main concern is can my PSU supply enough amps?

EVGA recommends 38 amps on the 12v rail and my PSU has 4 rails supplying 18 amps each. That's the way I think it works anyway please correct me if I'm wrong on that or any of this.

According to wikipedia a 6 pin power connector can output a maximum of 75 watts. That would mean each 6 pin connector would need 6.25 amps then because amps = watts / volts. If that's true then that's well below the 18 amps that each rail provides so it should be fine I would think. This mechanical drawing shows that the PCIE2 connector shares the 12v2 rail with the CPU power cable. The max TDP for a Q6600 is 105 Watts and this review shows that the Q6600 was using 102 watts. Going with the higher of the two the Q6600 should require 102 watts / 12 volts = 8.5 amps. According to the mechanical drawing the cpu power plug is connected to both the 12v1 and 12v2 rails so if the cpu was getting all it's power from that plug it would need 4.25 amps (8.25 amps / 2) from 12v1and 4.25 amps from 12v2. The only two parts of the GTX570 that have a risk of not having enough amps are the PCIE2 connector (because it shares 12v2 with the CPU power plug) and where it connects to the motherboard. If my previous calculations are correct though PCIE2 shouldn't be a problem because 4.25 amps (from the CPU) and 6.25 amps (from PCIE2) is 10.5 amps which is well below 18. And that's worst case scenario because I'm guessing that the CPU gets most of it's power from 12v1. That leaves the motherboard connection of the GTX 570 that might not have enough amps.

So to sum it up does my power supply have enough watts and does it have enough amps? I asked this question on the Tom's Hardware forum but I didn't get the technical answer I was hoping for. Could someone please tell me if my calculating everything right, I don't have a strong grasp of physics.

 

[SMOKEU]

I'd say you could easily get away with it, as OCZ normally builds good quality gear, rather than cheap crap. You may run into trouble if you try going to big overclocks, but otherwise it should be just fine.

 

[RollingThunder]

Wiseguy,

You'll be fine. To supplement Wiki, we have a sticky here that explains multiple "rails" and how they work:

http://www.overclockers.com/forums/showthread.php?t=548862

When you get setup and under some stress, check your voltage with your DMM and see how it is.

 

[EarthDog]

+1 to RT...

Not to mention that you dont add rails up to get the total value either. One has to read the label on the side of the PSU to find howmany watts for the 12v rail(s). Then take that wattage number and / by 12. Amps are a function of watts remember.

 

[wiseguy101]

+1 to RT...

Not to mention that you dont add rails up to get the total value either. One has to read the label on the side of the PSU to find howmany watts for the 12v rail(s). Then take that wattage number and / by 12. Amps are a function of watts remember.

I wasn't adding up the rails. Each rail provides 18 amps and one of the rails provides power for the CPU plug and the pcie2 plug. The CPU plug needs 4.25 amps and the pcie2 plug needs 6.25 amps for a total of 10.5 amps on one rail that can provide 18 amps. Could someone please tell me if this is correct I reasly want to understand this.

 

[EarthDog]

Oh ok, cool. Your sentence structure (not to your math paragraph) alluded to the fact that you can add up the rails to get the total value. That or I misread...

Anyway, your math, though making things more convoluted than it needs to be, is correct.

My only concern would be with the age of the PSU and it not being a great PSU to start with.

 

[wiseguy101]

Yeah I know it's not the greatest psu and it's 4 years old bit I haven't had any problems with it. I'm still considering upgrading because adding the GTX 570 leaves me little room for overclocking. The power supply I would upgrade to is an OCZ EliteXstream 800 watt psu do you have any thoughts on that? The reason my math was so convoluted is because I was trying to be as exact as possible and I don't understand all of it very well yet so I'm sorry about that.

 

[EarthDog]

With a proper 600W PSU, overclocking wouldnt be an issue. Im not sure how the EliteXstream is quality wise... but a quick google it looks good.