Help me out - getting ready for crossfire 4870

[portal]

I currently have the corsair 550w power supply and the gigabyte x38 motherboard. I've never crossfired/sli'd anything in my life so I'm wondering how much of a power supply I'll probably need to power these cards. I'm also planning on purchasing 1 4870 when it's released then waiting for the second to drop in price. Can anyone offer suggestions?

 

[godless]

i'd get 700watts minumum. 800watts to be sure it's not gonna have any problems. also what cpu do you have? are you overclocking?

 

[portal]

xeon E3110 no oc

 

[ovaltineplease]

does that x38 board support dual x16 pci-e 2.0 ?

from what tweaktown did on their x48 vs p45, x8 lanes can limit these cards so you definitely want dual x16 for the rated performance anyways

You could check amd's website for "crossfire certified power supplies" for the 3870x2 - they should work fine with the 4870. I think you may need an 8pin+6pin power per card so bear that in mind when you're shopping too.

 

[nachowarrior]

i'd just make sure you get plenty of amps on the 12v rail... 700watts does sound good... i'm running a 3870 with a 500 watt and 21 amps on the 12v rail now... but i don't think i have lots of overhead... the 4850 consumes slightly more power under load than my 3870 does under load... so i would chuck in that extra 200 watts just for a 4870 even though the power profile should be close to that of the 4850, maybe a little more, and 2 of them at the same time... if you can find the specs, just use the good old power formula, then overshoot it a bit. k? ( volts x amps = watts) i believe. good luck!

 

[dagger]

does that x38 board support dual x16 pci-e 2.0 ?

from what tweaktown did on their x48 vs p45, x8 lanes can limit these cards so you definitely want dual x16 for the rated performance anyways

You could check amd's website for "crossfire certified power supplies" for the 3870x2 - they should work fine with the 4870. I think you may need an 8pin+6pin power per card so bear that in mind when you're shopping too.

Yes, x38 supports dual pcie2.0x16. X38=x48.

 

[cliffro]

Nice CPU Portal, of course I'm biased....Your current PSU WILL work with 1, however when you purchase the 2nd card you will need to buy another PSU.

find one you like on this list(Warning they are expensive)
http://game.amd.com/us-en/crossfirex_components.aspx?p=3#ATI%20Radeon%E2%84%A2%20HD%203870%20X2%20/%20ATI%20Radeon%E2%84%A2%20HD%202900%20XT

I recommend waiting till you buy the second card to get it, it will give you time to save up for it. Although......

Take a gander @ requirements for the 3870x2

550 Watt or greater power supply with two 2x3-pin PCIe® power connectors required (750 Watt and four 6-pin connectors for dual ATI CrossFireX™
Link http://ati.amd.com/products/radeonhd3800/requirements.html

 

[Guest]

don't get CF 4870s... get 4870 X2... it will be better AND cheaper

 

[portal]

You think a 4870x2 will work on a 550watt?

 

[ovaltineplease]

You think a 4870x2 will work on a 550watt?

just depends on how many amps your power supply has on its 12V rails, refer to your company and then refer to the 4870x2 requirements whenever it goes live in 8 weeks.

Noone here can tell you that, because there is no way to know until its out - it should be slightly less requirements than 2 4870s tho I would imagine

 

[Sus-penders]

I'm assuming thats the VX550 you have? I think that power supply will be just fine. Corsair makes really good PSUs, very quality compenents, and their design philosophy is to build single 12v rails with all the amps deliverable on it. In this case, 41 amps, which will easily power two cards like the 4850's (110 watts).

4870's, couldn't tell you because we don't know how much power those will use yet. You'll likely be able to power those as well I imagine, but you might get uncomfortably close to the max power that PSU is able to provide.


You can read a review here http://enthusiast.hardocp.com/article.html?art=MTQyMCwsLGhlbnRodXNpYXN0 .


and specs http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004

 

[WR2]

You think a 4870x2 will work on a 550watt?

It will work with one 4870 quite easily.
That will give you time to check out the actual CF power requirements and look around for a new PSU later.
You can decide if you want to size your PSU for dual 4870 or with a CrossfireX setup of one 4870 and one 4870X2.