PCI express 2.0 x 16

[1Cane]

 I currently have a asus motherboard"P8Z68-VLX" that is a PCI express 2.0 X 16 and I am running two 6850 video cards.  I didn't realize that you can not run triple monitors in crossfire off of the 6850 video cards.  I am running triple monitors off of a single 6850  I am thinking of going to a 2gb 6950 but it is a PCI XPRESS 2.1x 16 video card.  So I have several questions. 
 Will the PCI XPRESS 2.1 work on my existing motherboard?
 Is there any advantage to go to a 2gb 6950? 
 Can you run a pair of 2gb 6950 in crossfire?

[Krusty]

I am a little fuzzy on this, but I "think" you can crossfire 6950s, as long as the slots are there.

Why not get a single card that is as powerful as both lesser cards? Saves power, can run the same monitors. As for 2GB yes it will make a difference in games when you are running multiple monitors. It uses more ram for any given filter, FSAA, Aniso, etc, the higher your screen resolution goes. So that 2GB is already being replaced with 3GB on the 7900 series cards, and will most likely be replaced with 4 GB I wager.

I have a 6970 2GB card with eyefinity ports that is running 3 monitors at 3840x1024 (3x 1280x1024 -- all I have) and it runs pretty smoothly. It also runs other games that are a little more graphically demanding than Aces High, with a nice framerate. Not pegged, but well above 30 (often 50s). The newer 7970 is probably even better at it.

[1Cane]

 What got me started here is while in B29s and approximately 26 k altitude I was only seeing two or three buildings in town.Skuzzy thought I might be pushing my card since it was only 1gb, I decreased the environmental mapping to approximately 20% and the problem went away. 
 I still don't know will a PCI Express 2.0 x 16 board be compatible with a PCI Express 2.1  x16 6950?
 I really doubt that I will go to 2 6950 cards since Ah is the only game I am playing now but I don't want to make the same mistake twice.

The system than I currently have turns out a constant 59-60 frame rate running three monitors at 5760 by 1080 with everything running except shadow on shadow and environmental mapping set at approx 20%.  I'm hoping to simplify it by going to the 6950 and increase performance.

[Krusty]

Turn down/off your environmental mapping. That's really a high-end feature. Takes up a lot of resources. It's a reflection map, after all.

I did some google searching and it looks like some other folks have 6950s in that motherboard.

Here's a guy with a sig saying he's running that mobo with a 1GB 6950
http://www.gamefaqs.com/boards/938738-/63819562

First guy on this page has one also:
http://legacy.tonymacx86.com/viewtopic.php?f=259&t=61810&view=next

I'd say it will take them.

[Skuzzy]

Adding another video card to your computer (Crossfire or SLI) will not increase the amount of available video RAM.

Real time environmental mapping is the most GPU intensive operation a video card can perform.  It requires a really fast GPU and lots of memory and for every notch of anti-alias you add, the memory requirements go up exponentially.

Currently, there are a handful of video cards available which can do it all and do it well.  All of them have 3GB of video RAM (or more) on them.

[SilverZ06]

I found this with a quick google search

" there is no speed difference between 2.0 and 2.1. PCI-e 2.1 adds the new management features for PCI-e which will be used mostly in the 3.0 cards (whenever that standard is released) but there is no difference in speed between the two types. There is however a difference in speed between 1.0 and 2.0 and a medium to high end graphics card used on PCI-e 1.0 will encounter a throughput bottleneck. To my knowledge no graphics card exists which requires a 2.1 slot and will not function on a 2.0 slot."

[gyrene81]

you could run a pci-e x16 3.0 video card in that mobo without any problems. the only thing a 6950 2gb video card will do is allow you to run a little more eye candy. shadows and environment mapping will still give you problems.