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SLI PSU Question

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April 30, 2012 3:51:01 AM

I'm still in the process of building a high end gaming desktop. I have the Thermal-take Chaser MLK Case. ASRock Extreme 4 Gen 3 Motherboard. Intel i7 2700k Sandy Bridge Processor. 16 gb of PC1600 Ram. 2.5TB of space with 1 - 2TB 7200 RPM HD and one older 600gb HD.

I'm currently using my old graphics card out of my old case the Asus GT 440 Graphics card. This Friday I'm going to be buy me a new graphics card and I'm wanting to make sure I get one that I can eventually SLI with an identical graphics card. I did alot of research and determined that I'm just going to stick with PCI 2.0 for now as the PCIE 3.0 doesn't seem to be worth buying a whole new processor for minimal performance upgrade.

I have the OCZ PSU Model # OCZ-ZT750W. On the +12V Rail it can handle a max load of 62 Amps.

I'm looking into getting the EVGA 012-P3-2066-KR GeForce GTX 560 Ti (Fermi) 448 Cores FTW 1280MB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card. On the power requirements it states that it requires 38 amps on the +12v Rail. I know this is probably a stupid question but it's been a very long time since I've ever built a computer ( roughly 10 years) so I just wanted to make sure whether or not my PSU would handle 2 of these cards. Obviously 38 x 2 is more than the max load of 62 Amps on the +12v rail however I didn't know if any of the other rails factored in somehow. I don't know a whole lot about PSU's and I'm still in the process of learning a little bit more about them but I thought for sure that I selected a pretty decent PSU figuring that 750W would be more than enough juice for this sytem.

My primary game of choice is World of Warcraft. I don't really play anything else aside from that. My wife plays The Sims 3 and that's about it. I know this graphics card might be a little over kill but I do really want to invest in some decent graphics. My budget is around $200-$300 per graphics card.

Any help would be appreciated.

Thanks,

More about : sli psu question

a c 251 U Graphics card
April 30, 2012 4:02:49 AM

If the power supply has one rail then it has 62 ampsc , if it has two rails then it has the total of the two rails. The only rails that count are the +12v rails and it sounds like your psu only has the one +12v rail.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

As an example if you look at this power supply it has 8 +12v rails and each one has 30a so the total of amps on the +12v rails for this psu is 240 amps.
a b U Graphics card
April 30, 2012 11:02:58 AM

inzone said:
If the power supply has one rail then it has 62 ampsc , if it has two rails then it has the total of the two rails. The only rails that count are the +12v rails and it sounds like your psu only has the one +12v rail.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

As an example if you look at this power supply it has 8 +12v rails and each one has 30a so the total of amps on the +12v rails for this psu is 240 amps.

:ouch: 
240a x 12v = 2880 watts
From a 1200 watt psu ?
If you look closer ( at the label ) it tells you that the combined 12v output is 1188 watts ( 99 amps )

It's rare for a psu's combined 12v rating's to equal it's actual output, that's why we don't add the 12v ratings
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a b U Graphics card
April 30, 2012 11:07:13 AM

Matorian said:
I'm still in the process of building a high end gaming desktop. I have the Thermal-take Chaser MLK Case. ASRock Extreme 4 Gen 3 Motherboard. Intel i7 2700k Sandy Bridge Processor. 16 gb of PC1600 Ram. 2.5TB of space with 1 - 2TB 7200 RPM HD and one older 600gb HD.

I'm currently using my old graphics card out of my old case the Asus GT 440 Graphics card. This Friday I'm going to be buy me a new graphics card and I'm wanting to make sure I get one that I can eventually SLI with an identical graphics card. I did alot of research and determined that I'm just going to stick with PCI 2.0 for now as the PCIE 3.0 doesn't seem to be worth buying a whole new processor for minimal performance upgrade.

I have the OCZ PSU Model # OCZ-ZT750W. On the +12V Rail it can handle a max load of 62 Amps.

I'm looking into getting the EVGA 012-P3-2066-KR GeForce GTX 560 Ti (Fermi) 448 Cores FTW 1280MB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card. On the power requirements it states that it requires 38 amps on the +12v Rail. I know this is probably a stupid question but it's been a very long time since I've ever built a computer ( roughly 10 years) so I just wanted to make sure whether or not my PSU would handle 2 of these cards. Obviously 38 x 2 is more than the max load of 62 Amps on the +12v rail however I didn't know if any of the other rails factored in somehow. I don't know a whole lot about PSU's and I'm still in the process of learning a little bit more about them but I thought for sure that I selected a pretty decent PSU figuring that 750W would be more than enough juice for this sytem.

My primary game of choice is World of Warcraft. I don't really play anything else aside from that. My wife plays The Sims 3 and that's about it. I know this graphics card might be a little over kill but I do really want to invest in some decent graphics. My budget is around $200-$300 per graphics card.

Any help would be appreciated


Thanks,

38 amps is the reccomendation for the system with the card, not just the card.
You don't double it for two cards
Your psu is more than sufficient for a pair of 560Ti's
a c 290 U Graphics card
April 30, 2012 11:42:03 AM

If you're playing World of Warcraft, don't get two graphics card in SLI, because World of Warcraft does not support it. If you have $500, get a GTX 680, that's the fastest single card in the world, and will be very fast for world of warcraft for 5 years.

http://www.hardwareheaven.com/reviews/1453/pg12/zotac-g...
a c 143 U Graphics card
April 30, 2012 11:58:31 AM

Sunius said:
If you're playing World of Warcraft, don't get two graphics card in SLI, because World of Warcraft does not support it. If you have $500, get a GTX 680, that's the fastest single card in the world, and will be very fast for world of warcraft for 5 years.

http://www.hardwareheaven.com/reviews/1453/pg12/zotac-g...

This has nothing to do with the thread topic.
a c 143 U Graphics card
April 30, 2012 11:59:14 AM

@OP

Simply the PSU will be more than sufficient, no worries.
a c 290 U Graphics card
April 30, 2012 12:05:12 PM

ilysaml said:
This has nothing to do with the thread topic.


Yes it does. OP plans on going for SLI for world of warcraft. I advised him not to. What's wrong?
a c 143 U Graphics card
April 30, 2012 12:15:40 PM

Sunius said:
Yes it does. OP plans on going for SLI for world of warcraft. I advised him not to. What's wrong?

Yea My Apology, didn't read the into well. And you're right.
April 30, 2012 1:19:21 PM

ilysaml said:
Yea My Apology, didn't read the into well. And you're right.


Owned!!!! HAHA jk But seriously just get a 680 or even a 580 they will run great. Oh ya if your a alliance these cards wont help you from me destroying your character.
a b U Graphics card
April 30, 2012 1:30:18 PM

delluser1 said:
:ouch: 
240a x 12v = 2880 watts
From a 1200 watt psu ?
If you look closer ( at the label ) it tells you that the combined 12v output is 1188 watts ( 99 amps )

It's rare for a psu's combined 12v rating's to equal it's actual output, that's why we don't add the 12v ratings


A common mistake that all too many make.
!