Cannot crossfire 2 4850's in Vista 64

[fromthecoast]

As the title says I cannot get my two 4850's working together in Vista 64. Crossfire isn't even listed under CCC. I tried uninstalling and reinstalling drivers, booting with 2GB of ram vs 4. My system is a dual boot and I could get it to run under 32 bit XP either. I have updated my mobo bios to the latest version. Where should I look for help with tis?

 

[Maziar]

download GPU-Z and check what it reports

 

[masterjaw]

List up the specs.. especially the mobo.

(I hope this isn't again one of the cases where people try to do CF in an SLI mobo)

 

[alikum]

List up the specs.. especially the mobo.

(I hope this isn't again one of the cases where people try to do CF in an SLI mobo)

I LOL'ed

 

[microterf]

assuming you have a Xfire mobo, and everything else is working fine. I was running into the same problem when I had 2 4850s.

The bad news is that for me, although both cards ran fine, my second card was reporting PCIe x1 instead of x8 like it should have, found out it was a faulty card. Like everyone else said, put your GPUz info up here

 

[masterjaw]

I LOL'ed

Well, I've encountered quite numerous people having problems doing CF in an SLI mobo. And he shows one specific signs of it (no crossfire option in CCC).

 

[fromthecoast]

OK. I got it figured out I believe. The new drivers and new CCC would not work with my cards and my setup. It is a Dell XPS 720 and is crossfire and SLI ready. I uninstalled the drivers that I have and installed the last recommended drivers that Dell suggested for the 4850. There must be some issues that they have to work around with on their mobo. Either way, the older driver and CCC worked. On the newer ones, it wasn't even showing crossfire as an option. Looks like things might actually be working right

XPS 700 "upgraded" to 720 mobo
E6600
4GB RAM
Vista 64
250 GB HD

 

[masterjaw]

I haven't encountered a mobo for lga775 socket with both CF and SLI capability. And according to Dell's site, mobo for XPS 720 has nvidia 680i chipset.

 

[fromthecoast]

Correct the 720 is 680i based. I believe the 700 was 580 based. One of the selling points for Dell was the fact that it was SLI or Crossfire capable. Crossfire definitely is working on my computer right now. This is my first dual card setup though so I can't comment on if SLI would have worked although I have seen several write ups of XPS 720 owners running both setups. It is 680 based but it is still a proprietary design since its BTX

 

[masterjaw]

No, it is not CF capable. See this.
http://techreport.com/articles.x/11212

Dell isn't the one who decide if they're PC is CF or SLI capable. It's the mobo installed that defines that capability. That one is an SLI mobo, not CF. Unless you got something like an x48 chipset which has both CF and SLI capability. Nvidia is not dumb to include its competitor's capability on their own chipset (same with AMD).

 

[fromthecoast]

It's 680 based and the 700 was 580? based and it also supported crossfire and SLI. I don't know what else to say. Also, crossfire is working on my computer, so I don't know what to say about that either.

 

[pauldh]

Crossfire is not impossible on a 680i chipset, but it requires a BIOS (hack) and Driver support. Never heard of it on a Dell before, but see links below:

http://www.dailytech.com/HP+Blackbird+Supports+CrossFire+and+SLI/article8788.htm
http://anandtech.com/systems/showdoc.aspx?i=3094&p=3

 

[Maziar]

Right^
http://www.tomshardware.co.uk/forum/page-245454_15_0.html

"Can you use SLI on a CrossFire board or can you use CrossFire on a SLI board ?
Well , in general , the answer is NO. But it's said that if you hack the drivers , you can use SLI on a CrossFire board or CrossFire on a SLI board.
Caution:There is no guarantee that if you hack the drivers then you use SLI on a CrossFire Motherboard or CrossFire on a SLI board, so do it at your own risk!"

 

[fromthecoast]

Well crossfire IS working on my computer now with NO hacks!

 

[pauldh]

If it's working, then Dell is using a "hacked" or modified BIOS / driver manipulation (like HP) in order to accomplish crossfire on 680i(explained in the links). Which could also explain why newer drivers no longer allow same to work.

Problem is, your married to Dell for driver support now.... so pray your future games will run on those old drivers.

 

[fromthecoast]

I would think that they are using a similar method as HP.

The new drivers worked but only after I installed the Dell drivers first and then installed the new drivers on top of that.