Im confused? SLI & CrossFire

[Bodaggit23]

I still think that's a bit dishonest.

Amperage is calculated using +12 rail output only.

If the OCZ 700 is 714.5watts after adding all the (+) power,
then my TX850 is 1035watts. lol

 

[FairDoos]

Right so the question of the day is What PSU should i get? Or Should i stick with the one i have? I was thinking that (I think it was) 700W Corsair Modular it says its CrossFire Ready soo?

 

[Bodaggit23]

Right so the question of the day is What PSU should i get? Or Should i stick with the one i have? I was thinking that (I think it was) 700W Corsair Modular it says its CrossFire Ready soo?

Yes, that's a very nice PSU, but as suggested, you could try to run both cards with your current PSU, and if it doesn't work, you could always upgrade later.
Unless you were planning to order both at the same time.?

The modular is very nice, as stated, but if you have lots of room in your case, and some cable management, the non-modular unit is much cheaper.

CORSAIR CMPSU-750TX ($119.99)
($99.99 after $20.00 Mail-In Rebate)

Compared to the Modular version

CORSAIR CMPSU-750HX ($169.99)
($159.99 after $10.00 Mail-In Rebate)

 

[bomberboysk]

Yes, that's a very nice PSU, but as suggested, you could try to run both cards with your current PSU, and if it doesn't work, you could always upgrade later.
Unless you were planning to order both at the same time.?

The modular is very nice, as stated, but if you have lots of room in your case, and some cable management, the non-modular unit is much cheaper.

CORSAIR CMPSU-750TX ($119.99)
($99.99 after $20.00 Mail-In Rebate)

Compared to the Modular version

CORSAIR CMPSU-750HX ($169.99)
($159.99 after $10.00 Mail-In Rebate)

This is also a great option that is modular, just as good as the corsair, but a bit cheaper: (I love the zalman units, nice large slow fan that moves alot of air, and heatpipes to cool and spread the area over a great amount of fins. Very nice units)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817379006


The OCZ ModXStream will run two 4890s in crossfire and then also that Phenom 9950 though.... You wouldnt even be pulling 500W(its somewhere around 450W) off the +12v rails with two 4890's and the phenom.

I don't think so.

The 700W ModXStream Pro only has 552watts on the 12+ rail.

ATI recommends at least 600watts for Crossfire.

600W Power supply, not 600W on the 12v rails.

Even at the absolute maximum power draw, the cards can only get 225W of power(which they draw a good bit less than) as slot provides 75W, and each 6pin is 75W.

I still think that's a bit dishonest.

Amperage is calculated using +12 rail output only.

If the OCZ 700 is 714.5watts after adding all the (+) power,
then my TX850 is 1035watts. lol

There are multiple rails, that 600W is referring to a standard 600W. Most 600W quality units will have 430-500W on the +12v rail. That is why power supplies do not only have a +12v rail.

 

[Bodaggit23]

600W Power supply, not 600W on the 12v rails.

Even at the absolute maximum power draw, the cards can only get 225W of power(which they draw a good bit less than) as slot provides 75W, and each 6pin is 75W.

What's the difference in this case? The OCZ psu in question still states 552watts on the +12 rails, which is not 600watts...

You trying to say that any 600 psu will run 4890's in Crossfire? Confused...

 

[bomberboysk]

What's the difference in this case? The OCZ psu in question still states 552watts on the +12 rails, which is not 600watts...

You trying to say that any 600 psu will run 4890's in Crossfire? Confused...

PSU Wattage and +12v rail wattage are two different things. And yes, a quality 600W should be able to run 4890's in crossfire. Those are not +12v rail ratings, those are entire unit wattage ratings.

Look at the power draw of a system with two 4890's and an i7:

Second one, CF is crossfire, 420W peak load and that includes an i7 920 at 3.8Ghz. And these are power draw from the electrical socket, so you have to factor in effeciency and its actually drawing less than 400W.

 

[Ethan3.14159]

This all seems awfully familiar. Oh wait, this exact discussion happened on the last page....

 

[FairDoos]

Arr right thanks guys ive decided what im going to do!

1, Wait for nVidias response on DirectX 11
2, If there as better and cheaper (nVidiaDirectX11Card) Ill be getting 2
3, If my PSU wont support that much ill just go and get another
4, THANKS FOR THE HELP!

p.s I think this extra information should be posted in the Official SLI & CrossFire thread