So I got my 6950's. Crossfire worked fine with assigning 1 worker per card. You were right though and this caused high CPU load. I turned off the Crossfire and luckily I did not need a VGA Dummy as I run dual head (two monitors with one pluged into each GPU). This produced the same Mhash/s but less CPU usage and more stability.

4xxx series video cards do not support openCL so you CANNOT mine with them. You will need to purchase a 5xxx or 6xxx series video card in order to mine.

Thanks for the info dishwara. I will try option 4 when I get home and update with the info.

I am also experiencing this issue on my 6950's. AMD updated the forum post with "Our engineers are currently working on the problem." So hopefully this will be resolved with future drivers.

http://forums.amd.com/forum/messageview.cfm?catid=390&threadid=128404&enterthread=y

I think the problem is that for most people that are not tech-savy, bitcoins are to hard/confusing to even get started. As we all know, generally men are more tech-savy then women. In many technical jobs that I have had, it seems the ratio of men to women is 20:1. I think it has to do with how we grow up, men are more likely to play on a computer. This may change as more and more kids get into social networking and such. Although, everything has been dumbed down for them so much that they my not try to spend the time to learn anything.

A great price per performance are the 6950's that can be unlocked to 6970's.

The following card can be unlocked:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127555&cm_re=6950-_-14-127-555-_-Product

You can unlock it by following these directions:

http://www.techpowerup.com/articles/overclocking/vidcard/159


These can do over 400Mhash/s per card for under $250 after the mail in rebate.

My current mining rig:

1 6950 w/ unlocked shaders
2 900
3 2
4 750W
5 72c
6 28c
7 65%
8 24/7
9 Issues with crashing if Flash Video is played, seems to be a driver issue.

Wow! This GUI is awesome. I love the On-Screen display. Thank you so much!

Thank you! This worked like a charm.

I found some great information on mining with the 5770 at the following blog:

http://www.smpake.com/?p=59

I was able to duplicate smpake's results on my own XFX 5770.

Getting my two 6950's in a few days, will update this with my findings.

This "sharing the workload" cause more/less/equal Mhash/s compared to using the VGA Dummy?

As previously said by another user, I would not buy 6990's. A better price per performance are 6950's that are unlocked to 6970's.

The following card can be unlocked:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127555&cm_re=6950-_-14-127-555-_-Product

You can unlock it by following these directions:

http://www.techpowerup.com/articles/overclocking/vidcard/159


These can do 400Mhash/s per card for $270. 6990 can do 800Mhash/s per card for $750+. As you can see, building multiple machines with 6950's is a much smarter option.

I thought that crossfire makes 2 cards one, did not know that the OS could still see them separately. So what you are saying is that I can run crossfire but will still be able to run one worker per GPU? Power consumption is not a problem for me as I have included utilities.

What is the downside to running crossfire and mining with one worker? Will this have less Mhash/s then doing two cards/no crossfire and one worker per card? Does anyone have any data for this or links?