Is this CF really working with x1 and x16?!

[CaptainTom]

So about a month ago I asked why I was having scaling issues with some of my games. I thought I had a x4 and a x16 crossfire setup. However GPU-Z says I have a x16 and a x1. Here's the other thing: any game that needs the scaling to work to get 60+ FPS does (Crysis 2, Metro: 2033, Sleeping Dogs, etc.).

I guess I just want any confirmation that the limited bandwidth could be what is stopping scaling past 60 FPS, and if this is bad.

CPU: i5-3570k
Mobo: AsRock Pro4m
GPU: HD 6950 CF

 

[Sunius]

This one? http://www.asrock.com/mb/Intel/Z77%20Pro4-M/

If so, Top slot supports x16, middle slot supports x4 and bottom slots supports x1. Which slots do you have the cards at?

Also, what is GPU usage?

 

[blazorthon]

PCIe 2.0 x4 and below can be bottle-necks (especially below PCIe 2.0 x4) for a Radeon 6950, especially in CF.

 

[CaptainTom]

This one? http://www.asrock.com/mb/Intel/Z77%20Pro4-M/

If so, Top slot supports x16, middle slot supports x4 and bottom slots supports x1. Which slots do you have the cards at?

Also, what is GPU usage?

I have the main card in the top slot, and the second card in the middle slot. This is the only way I can fit them in my matx case. So you are sure the middle one runs at x4? GPU-Z says x1.

 

[CaptainTom]

PCIe 2.0 x4 and below can be bottle-necks (especially below PCIe 2.0 x4) for a Radeon 6950, especially in CF.

The benchmarks I looked at basically said x4 doesn't make much of a difference, but that was a year or two ago. However I can easily imagine that x1 would be a huge problem. If it is x1, how can I still be getting 70-100% scaling in metro: 2033 etc.

 

[blazorthon]

Can you post a screenshot of your GPU-Z showing a PCIe 2.0 x1 connection?

70+% on that card looks like a PCIe 2.0 x4 connection, not PCIe x1. If it was x8 or x16, then it would be more like 85 or 90% and up instead of 70% and up scaling, that's what I meant by x4 starting to be a bottle-neck. IT's a bottle-neck, but not a huge one for that card.

 

[CaptainTom]

Can you post a screenshot of your GPU-Z showing a PCIe 2.0 x1 connection?

70+% on that card looks like a PCIe 2.0 x4 connection, not PCIe x1. If it was x8 or x16, then it would be more like 85 or 90% and up instead of 70% and up scaling, that's what I meant by x4 starting to be a bottle-neck. IT's a bottle-neck, but not a huge one for that card.

This first one is the primary card at x16

http://i1156.photobucket.com/albums/p563/Tom_Splittstoesser/3a73c278.jpg

http://i1156.photobucket.com/albums/p563/Tom_Splittstoesser/0af476ae.jpg

 

[CaptainTom]

That's not how you post images to the web. You have to upload the picture to something such as Photobucket and then give us a link to the image stored on photobucket or whatever other service you use for that. Giving us the link to the file on your hard drive doesn't do any good because we can't access your hard drive.

Yeah ik, i fixed it now though right?

 

[blazorthon]

That's not how you post images to the web. You have to upload the picture to something such as Photobucket and then give us a link to the image stored on photobucket or whatever other service you use for that. Giving us the link to the file on your hard drive doesn't do any good because we can't access your hard drive.

 

[blazorthon]

It does say that it's running with only one PCIe 2.0 lane. Odd if you are using the proper PCIe setup for that motherboard and even more odd if you're getting proper scaling.

Can you post benchmarks to compare between CF disabled and CF enabled?

 

[CaptainTom]

It does say that it's running with only one PCIe 2.0 lane. Odd if you are using the proper PCIe setup for that motherboard and even more odd if you're getting proper scaling.

Can you post benchmarks to compare between CF disabled and CF enabled?

With furrmark I get 35FPS with one card, and 66 FPS with both in CF.

Some games don't scale, but the only one that kinda concerns me is FC2 not scaling. Otherwise Metro, Crysis, and sleeping dogs all get 60-100% scaling.

 

[blazorthon]

Well, it seems to be working, albeit not how I'd expect it to. What resolution do you play at?

EDIT: I just thought about it and maybe it does make sense. Crossfire relies on a master/slave setup. The master card is the one that the CPU talks to, so maybe it's the only one that needs the most PCIe bandwidth. The cards need to talk to each other too, but that is what the CF connector is for. If your master card was in a PCIe x4 or worse slot, then you'd probably have far more serious issues. Well, that's me theory of it given your situation.

 

[CaptainTom]

Well, it seems to be working, albeit not how I'd expect it to. What resolution do you play at?

EDIT: I just thought about it and maybe it does make sense. Crossfire relies on a master/slave setup. The master card is the one that the CPU talks to, so maybe it's the only one that needs the most PCIe bandwidth. The cards need to talk to each other too, but that is what the CF connector is for. If your master card was in a PCIe x4 or worse slot, then you'd probably have far more serious issues. Well, that's me theory of it given your situation.

I play at 1080p. The only games that don't scale, are ones that get 70+ FPS with just one card. I am guessing CF is just more optimized to not depend on dual bandwidth, and when it runs out of bandwidth, the game doesn't need any more anyways...

 

[CaptainTom]

Best answer selected by CaptainTom.

 

[Mousemonkey]

This topic has been closed by Mousemonkey