Will 2 8800GTS 320's force me into a new power supply?

[HomeyFoos]

I just bought 2 320's and I realized I may have to upgrade my psu. What do you guys think? I'm currently running a single 7900GTX.

 

[Scotteh]

I am having to upgrade my PSU for a single one. Let alone two.

I am currently using a 500w PSU but it the important factor to consider is the ampage. I am upgrading to a 600w PSU as i run several other power hungry devices, as will many other people.

The 8800GTS requires 2x 12 Volt rail supply with minimum of 13 amps each.

So make sure you check this also when you get your new PSU. I'd imagine your going to be looking at a 700w PSU with dx 12 volt rail with 26 amps on each (Seeing as you have 2 gts's).

 

[Aberforth]

An example for a bad investment....you could have bought 2X640MB GTS. OCZ 600W PSU is OK for your setup though.

 

[Captante]

Originally posted by: HomeyFoos
I just bought 2 320's and I realized I may have to upgrade my psu. What do you guys think? I'm currently running a single 7900GTX.

With your system (assuming you have just whats listed in your sig + an optical drive) it'll be pushing your luck with the 600 watt OCZ. My estimate is power draw under load will be right around 600 watts with 2 GTS's so it'll be running at peak output & if you have more stuff besides the components listed you'll be pushing beyond its limits & if you have more stuff besides the components listed you'll be pushing beyond its limits which can result in catastrophic failure & might take other components along with it. I'd give serious thought to getting somthing in the 750-850 watt range for 8800 SLI, so you'll have some breathing room instead.

Originally posted by: Aberforth
An example for a bad investment....you could have bought 2X640MB GTS. OCZ 600W PSU is OK for your setup though.

If the OP had your 700 watt OCZ I'd say he would be fine & I think the 600 watt OCZ will JUST hold the system with GTS's in SLI, however I wouldn't try it myself considering what the 2 graphics cards just cost him ... IMO its just not worth the risk of killing them if the PSU blows out under load.

 

[Aberforth]

Originally posted by: Captante
With your system (assuming you have just whats listed in your sig + an optical drive) it'll be pushing your luck with the 600 watt OCZ. My estimate is power draw under load will be right around 600 watts with 2 GTS's so it'll be running at peak output & if you have more stuff besides the components listed you'll be pushing beyond its limits which can result in catastrophic failure & might take other components along with it. I'd give serious thought to getting somthing in the 750-850 watt range for 8800 SLI, so you'll have some breathing room instead.

320 MB version draw less power. You may be right yea..

 

[HomeyFoos]

Well,

I bought them with the intent of stepping up to GTXs or if I have time, the 8900series. Either way I'm fine but I have a buyer for my 7900GTX and that thing gets more ancient as the days pass. I figured I should pull the trigger now and let him pay for one of my GTSs then step up in 90 days. This way, I don't have to spend $1200 all at once, I can span that cost out over 90 days. In any event, it's my money, so let me spend it as I would.

Also, I realize that when I step up I will need more power and I've looked at the Quad Rail PC-P&C 750. New it's $239ish and refurbed (I wouldn't normally look at a refurbed PSU but I have a good friend w/ a 1kw PCP&P quad refurb running 2 8800GTX and he is quite happy) it's $169 negotiable from the factory with the same warranty.

As to my current PSU, it is the OCZ 600w Powerstream (max wattage is 700w) with 2 12v rails at a max output current of 35a (20a normal) each. I think I fall into a gray area here. The SLiZone website mentions the OCZ 700w Gamer Xtreme, and the stats aren't much different from mine (seemingly, though when it comes to power, I really only know numbers and to stay away from cheap psu's) but I've seen people running gear at less than the recommended wattage without issues as long as the PSU was stable. And when I bought it, this PSU was the most stable that didn't cost $600. Sorry, I should have included the info about my current PSU in the first post.

 

[HomeyFoos]

Also, other than the listed equipment, I have the usb ports from my 2 dell monitors (2007wfp and 2407wfp) and the card reader from my 2407. I have keyboard and mouse, a gamepad, and usb wifi and that's it. I figured I would be very close with 2 new cards but my logic was that since they were 320's they had to have less power draw than the 640s (even if it was minimal) and my current PSU was pretty highly rated. So again, if I could push the purchase of a 750-850w quad-rail PSU back even til the first of the month, I would be fine. I could do it tomorrow but that would suck up most of my fun money til March 1. And I have drinking and such to get done so I'd prefer if I could be fine with my current PSU for the short term.

 

[vhx]

http://www.anandtech.com/video/showdoc.aspx?i=2870&p=25

According to anandtech's article, 2 GTX's consumption is ~410W for most games. Expect GTS to be lower than that.

 

[Captante]

Originally posted by: HomeyFoos
Well,

I bought them with the intent of stepping up to GTXs or if I have time, the 8900series. Either way I'm fine but I have a buyer for my 7900GTX and that thing gets more ancient as the days pass. I figured I should pull the trigger now and let him pay for one of my GTSs then step up in 90 days. This way, I don't have to spend $1200 all at once, I can span that cost out over 90 days. In any event, it's my money, so let me spend it as I would.

Also, I realize that when I step up I will need more power and I've looked at the Quad Rail PC-P&C 750. New it's $239ish and refurbed (I wouldn't normally look at a refurbed PSU but I have a good friend w/ a 1kw PCP&P quad refurb running 2 8800GTX and he is quite happy) it's $169 negotiable from the factory with the same warranty.

As to my current PSU, it is the OCZ 600w Powerstream (max wattage is 700w) with 2 12v rails at a max output current of 35a (20a normal) each. I think I fall into a gray area here. The SLiZone website mentions the OCZ 700w Gamer Xtreme, and the stats aren't much different from mine (seemingly, though when it comes to power, I really only know numbers and to stay away from cheap psu's) but I've seen people running gear at less than the recommended wattage without issues as long as the PSU was stable. And when I bought it, this PSU was the most stable that didn't cost $600. Sorry, I should have included the info about my current PSU in the first post.

Again, you have a good quality PSU, but I think you''ll be taking a chance even with the two 320mb GTS's & I wouldn't even consider trying to run SLI'ed GTX's on it. Also remember the maximum power is maximum peak power, not the load it was intended to supply for extended periods of time (like hours of gaming).

I'm pretty sure you'll be ok short-term running with the Powerstream 600, but if it were me, I'd be snagging somthing new asap... btw $169 for a refurb PC Power & Cooling isn't the best deal when you can get comparable brand-new PSU's for about the same money.


SILVERSTONE SST-ST75ZF - 750 watt @ $179

ETASIS ET750 - 750 watt @ $174

FSP Group (Fortron Source) FX Series FX760-E - 760 watt @ $179 w/$15 MIR

 

[thilanliyan]

Originally posted by: Scotteh
The 8800GTS requires 2x 12 Volt rail supply with minimum of 13 amps each.

So make sure you check this also when you get your new PSU. I'd imagine your going to be looking at a 700w PSU with dx 12 volt rail with 26 amps on each (Seeing as you have 2 gts's).

Ummm...wha you just said is not right. I'm running My GTS (OCed) on a 420w PSU, with everything else in my sig (+2 more hard drives + 7 total fans) and it has a SINGLE 12V rail with 30A on that rail. There is no stipulation that says you NEED a dual rail PSU. The minimum amperage you quoted may be right but I think most PSUs come with 18A on each rail nowadays. Also, finding a dual rail PSU with 26(!!)A on each rail might be a bit difficult except maybe for those beefy 800-1000w PSUs. You don't need that much to run even GTX SLI:
http://techreport.com/reviews/2007q1/geforce-8800-sli/index.x?pg=14

That is FULL SYSTEM power consumption. Of course if you add in OCed CPUs, GPUs, and several other components you need more than the ~400w but you definitely don't NEED a monstrous PSU.

 

[Gamingphreek]

99% of the comments in this thread are BS. You will be fine with your current PSU. I wish people would stop blowing this out of proportion. Even SLIed GTX's, as stated earlier draw only 410watt for the ENTIRE SYSTEM. Stop polluting peoples minds with the need for huge 1 Kw PSUs!!!!!!!

-Kevin

 

[Captante]

Originally posted by: Gamingphreek
99% of the comments in this thread are BS. You will be fine with your current PSU. I wish people would stop blowing this out of proportion. Even SLIed GTX's, as stated earlier draw only 410watt for the ENTIRE SYSTEM. Stop polluting peoples minds with the need for huge 1 Kw PSUs!!!!!!!

-Kevin

That depends on the system ... my main PC draws around 550-570 watts under load with a single 8800GTX (measured using my Kill-a-watt) & as far as I know the 8800 GTX by itself pulls somthing like 280 watts under load & the 640mb GTS pulls in the are of 240 watts which means just the GPU's alone are going to pull more then 410 watts.

Just where did you get these numbers?

 

[thilanliyan]

Originally posted by: Captante
Just where did you get these numbers?

Look at my post above Gamingphreek's. Techreport shows the same.

These are also system power consumption:
http://www.bit-tech.net/hardware/2006/11/08/nvidia_geforce_8800_gtx_g80/18.html
http://enthusiast.hardocp.com/article.html?art=MTIxOCwxNiwsaGVudGh1c2lhc3Q=
http://rage3d.com/reviews/video/nvidia8800/index.php?p=7


Granted these are probably bare systems and not overclocked, so you will have to factor that in when you add more components. I believe NVidia stated something like 140-180w for just the GTX power consumption.

 

[Gamingphreek]

That depends on the system ... my main PC draws around 550-570 watts under load with a single 8800GTX

How many HDD's and how much RAM could you have that draws that much. A single GTX is not going to force your system to draw that much power...sorry it just isn't.

As for your link, even though it isn't stated, I believe it is Total System Power Consumption not just Video Card.

-Kevin

 

[Captante]

Originally posted by: thilan29

Originally posted by: Captante
Just where did you get these numbers?

Look at my post above Gamingphreek's. Techreport shows the same.

Interesting read... still seems a bit low for the total system draw if he has more then the bare minimum of components though. I have a 700 watt Seasonic which does supply considerably more power then even my main PC draws
(I understand mine is on the high end of power draw) & even so I'd be thinking of upgrading it if I decided to snag another GTX.

I know a decent 450-500 watt PSU can handle a normal system (1x HD & 1x Optical) with 1 GTX, but personally I wouldn't do that myself either. I'm not suggesting that anyone needs 1000 watts of power unless you plan on running a refrigerater inside your PC, but I prefer a wider margin between the peak power available & my draw under load then that would give me.

 

[Gamingphreek]

I know a decent 450-500 watt PSU can handle a normal system (1x HD & 1x Optical) with 1 GTX, but personally I wouldn't do that myself either. I'm not suggesting that anyone needs 1000 watts of power unless you plan on running a refrigerater inside your PC, but I prefer a wider margin between the peak power available & my draw under load then that would give me.

What kind of "normal" computer only has one optical drive??

But to your point...I don't see why in the world you would upgrade from a 700 Watt Seasonic (Arguably the best maker of consumer grade PSU's) just because you add another Video card. Look at SPCR's graphs on efficiency. Your "wider margin" more times than not equals lower efficiency.

Like I said earlier, these rash claims about huge PSU's have no basis.... everyone outside of SLI/Crossfire users or users with massive amounts of HDD's (or servers etc...) will have no problem at all with a 500-600 Watt Quality PSU.

-Kevin

 

[thilanliyan]

Originally posted by: Captante
I know a decent 450-500 watt PSU can handle a normal system (1x HD & 1x Optical) with 1 GTX, but personally I wouldn't do that myself either. I'm not suggesting that anyone needs 1000 watts of power unless you plan on running a refrigerater inside your PC, but I prefer a wider margin between the peak power available & my draw under load then that would give me.

I agree with you there. Also, measuring consumption at the wall outlet, you must also consider your own PSU efficiency don't you?? (ie. if you have a less efficient PSU, your perceived power consumption would be higher than a PSU with a higher efficiency)(don't think I'm saying yours in inefficient...I know nothing about your PSU )

The systems in the links I gave are more than likely bare systems since they are trying to test the GPU consumption (or at least get a rough idea of it).

 

[HomeyFoos]

I looked at benchmarks and that number fluctuated from game to game. The doom 3 engine apparently got the system draw with 8800GTXs up to 488. But if that is true, I would still have plenty of headway at 600w. Also, SLi did not seem to double the required wattage. In the BF2 test, the requirements for a single GTX was 280 and the SLi was 406.

On the other side of that coin, my friend who has the PCP&C 1kw psu experienced it a little differently. He has a 'normal' system (usb saitek glowy keyboard, razer mouse, 2 hdds, 1 soundcard, 2 dvds, etc) and he could not run his 8800GTXs with the OCZ GamerXreme 700w. Well, they ran, but he would crash in 3dmark 06. He got the 1kw and it ran fine. I was with him in vent for most of this process so I am pretty much a first-hand witness.

I'm somewhere in-between you guys. I think for the short term I will be ok. But eventually, I will need to upgrade and I cite my friend's experience as an example.

 

[Captante]

Originally posted by: Gamingphreek

That depends on the system ... my main PC draws around 550-570 watts under load with a single 8800GTX

How many HDD's and how much RAM could you have that draws that much. A single GTX is not going to force your system to draw that much power...sorry it just isn't.

As for your link, even though it isn't stated, I believe it is Total System Power Consumption not just Video Card.

-Kevin

My system doesn't represent the norm, even here on AT ... when tested I had 6 SATA HD's, 2 IDE optical drives, X-Fi w/front bay, Promise PCI RAID controller, Asus Crosshair 590-SLI, A64 5000+ @ 2.8ghz w/Zalman CNPS9500, EVGA 8800GTX, 6 x 120mm fans, 2 x 80mm fans, 4gb DDR2-800mhz, 1 x 3.5 floppy, 1 x memory card reader & 2x 4 port USB hubs powered off the ports. (no AC connections) running off of a Seasonic M12 SS-700HM 700 watt PSU.

Power draw under load (running 3D-Mark 2006) measured directly from the plug was steady at a bit over 550 watts, ... since then I've removed 2 of the HD's & the Promise PCI RAID controller so it should be pulling a bit less now, but just as an example for you, my APC 1500VA UPS will only run this PC for abput 5 minutes (with 24 inch LCD on) before having to shut down.

Edit: When tested I also had the Razor Tarantula USB keyboard (since replaced with the Saitek Eclipse II)

 

[Captante]

Originally posted by: HomeyFoos
I looked at benchmarks and that number fluctuated from game to game. The doom 3 engine apparently got the system draw with 8800GTXs up to 488. But if that is true, I would still have plenty of headway at 600w. Also, SLi did not seem to double the required wattage. In the BF2 test, the requirements for a single GTX was 280 and the SLi was 406.

On the other side of that coin, my friend who has the PCP&C 1kw psu experienced it a little differently. He has a 'normal' system (usb saitek glowy keyboard, razer mouse, 2 hdds, 1 soundcard, 2 dvds, etc) and he could not run his 8800GTXs with the OCZ GamerXreme 700w. Well, they ran, but he would crash in 3dmark 06. He got the 1kw and it ran fine. I was with him in vent for most of this process so I am pretty much a first-hand witness.

I'm somewhere in-between you guys. I think for the short term I will be ok. But eventually, I will need to upgrade and I cite my friend's experience as an example.

Actually I think you & I are on the same page, I agree that you should be ok short-term ... also I prefer to over-build everything a bit too.

 

[Captante]

Originally posted by: Gamingphreek

What kind of "normal" computer only has one optical drive??

-Kevin

Outside of AT, most normal PC's only have one optical drive ... scary, I know!

Also I'm well aware that I have a great power supply, however I like the fact that its capable of pushing out the roughly 500 watts my PC currently draws with a 200 watt surplus... if I added another GTX that surplus would be gone so I would likely go for an 850 watt unit to replace it & transfer the Seasonic into my 2ed machine.

I know its a bit of over-kill, thats just the way I prefer to do it.

 

[Aberforth]

Oced E6600 3.75 Ghz @ 1.4
2 GB DDR Ram
2 X 8800 GTX SLI
2 X 120 MM High Performance Fans
1 X Creative Sound card
6 X USB Devices
1 X SCSI 10K RPM HDD
1 X DVD RW

= 638 W :thumbsup:

 

[HomeyFoos]

Im drawing about 434 watts according to a calculator. It factored my OC at 125w. With a second card in my pciex16 slot, it said 539. It will be close.

 

[Gamingphreek]

Originally posted by: HomeyFoos
Im drawing about 434 watts according to a calculator. It factored my OC at 125w. With a second card in my pciex16 slot, it said 539. It will be close.

Those PSU calculators are horribly inaccurate IMO.

-Kevin

 

[CP5670]

My system doesn't represent the norm, even here on AT ... when tested I had 6 SATA HD's, 2 IDE optical drives, X-Fi w/front bay, Promise PCI RAID controller, Asus Crosshair 590-SLI, A64 5000+ @ 2.8ghz w/Zalman CNPS9500, EVGA 8800GTX, 6 x 120mm fans, 2 x 80mm fans, 4gb DDR2-800mhz, 1 x 3.5 floppy, 1 x memory card reader & 2x 4 port USB hubs powered off the ports. (no AC connections) running off of a Seasonic M12 SS-700HM 700 watt PSU.

Power draw under load (running 3D-Mark 2006) measured directly from the plug was steady at a bit over 550 watts, ... since then I've removed 2 of the HD's & the Promise PCI RAID controller so it should be pulling a bit less now, but just as an example for you, my APC 1500VA UPS will only run this PC for abput 5 minutes (with 24 inch LCD on) before having to shut down.

Did you take your power supply's efficiency and the monitor's power draw into account? Otherwise, the hard drives are probably contributing a lot to the total. My rig should be similar to that in power consumption aside from the hard drives (have only two memory sticks and no RAID card, although an X1900XTX uses a bit more power on load than an 8800GTX), but the system itself only uses about 230W, with 400W measured at the outlet.