Crossfire question

[Venturi]

I was looking at some of the charts and I have 1 ATI 4870. I am thinking of hooking another in crossfire with mine. Though when I look at the charts the crossfire sometimes is worse then just 1 card.

So I would like to know is it worth it to crossfire the 2 of them or is it just in some cases that one is better?

 

[todd5854]

To me, it's understood as this.

Video cards (yours at least) are PCI "X16" slots. You'll have to look online to see if your crossfire supported motherboard has 2 X16 slots, and not 1 X16 and 1 X8 slot. I believe this is the case with my K9N SLI Platinum by MSI.

I am not telling you this from my own experience, so I could be completely wrong.

 

[xxcoop42xx]

To me, it's understood as this.

Video cards (yours at least) are PCI "X16" slots. You'll have to look online to see if your crossfire supported motherboard has 2 X16 slots, and not 1 X16 and 1 X8 slot. I believe this is the case with my K9N SLI Platinum by MSI.

I am not telling you this from my own experience, so I could be completely wrong.

actually it really doesnt matter about if it runs at 16x/16x, there is an article that compares 16x/16x to 8x/8x and actually there is minimal preformance loss if any (its like 1-3 fps) so 8x/8x CF is just as good as 16x/16x. what makes the difference is if both the slots are pci-e 2.0 or not as a pci-e 1.0 slot would limit your card more than running a card at 8x link speed. take a look here. the cards are a little older but there really isnt that much difference.

http://www.tomshardware.com/reviews/crossfire-meets-pci-express,1761-7.html

 

[Venturi]

My motherboard has two pci-e 2.0, so if I understand you I shouldn't see and frame rate drop if I crossfire the cards?

 

[xxcoop42xx]

yes thats right, just because they run at 8x/8x link speed doesnt really mean anything but if it was 8x/8x with one being pci-e 2.0 and the other pci-e 1.0 you would notice a drop in preformance. because pci-e 1.0 is half the speed of 2.0 therefore bottlenecking your 2.0 card, im doing 4870/4850 cf next month and my asus p5q pro mobo has 2x pci-e 2.0 at 8x/8x too. so your golden

 

[SpinachEater]

Forget about PCIe1.0, it is dead. If you have a mobo with only PCIe1.0 slots then you need to get a new mobo, not a second GPU.

What motherboard do you have? What resolution is your monitor? Why do you want to xfire? (<- a serious q) Is there a particular game that you want higher FPS in? Pretty much you shouldn't see a FPS drop with xfire even in x8/x8 mode. The only reason you would see a drop in xfire FPS is if the drivers aren't ready for a certain game like Mirrors edge for example. Not sure if they fixed it in 9.1 drivers but the 4870x2 was at the bottom of the list at one point.

Are you talking about Toms GPU charts? Their GPU charts are Fd up. They have a 4850 doing better than xfire 4870 and the 4870x2 in a Crysis test. That is absurd. In other tests they have xfire 3870 beating xfire 4870 . Who knows what they did but that is pretty much a steamy pile.

Here is what xfire should be like
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/9159-ati-hd4870-hd4850-crossfire-performance-review.html