It is possible to set up triple Crossfire with a 6870x2 and a 6870, Tom's did it in an article analyzing microstuttering, and actually found that microstuttering was significantly reduced when you did triple Crossfire with the 6870 and 6870x2, compared to 2 6870s in Crossfire. You'll be fine as long as you don't try to Crossfire more than two cards, just make sure that your PSU can handle it.
Thank you friend. OK then, i will order my GPU. It's not about the gaming actually.
I want to increase the power for brute force.
I'm using a Fractal Design Newton R2 1K. Will this enough to power it up on long time? Example: the calculation on brute force some times found on 3rd day even longer on some case. GPU loads about 90%, CPU loads about 70% on each core.
List of my current device (power consumption):
Core i7 2600K / Asus P8Z68 Deluxe / 4 HDD / 2 SSD / 1 DVD / WiFi card / 6 Fans / 6870 GPU .. will add now 6870x2.
Will 1K PSU enough to handle this on 24hrs/5days non stop?
Windows Experience Index is not always a good indicator of performance. If you are concerned about your memory not performing like it should, you should try looking at some other benchmarking utilities for that. I think PCMark has a test to determine how fast your memory can perform. Are you using a 32 bit OS? If so, you may have less memory to work with with the Triple Crossfire setup due to addressing limitations of a 32 bit operating system,
Yes, you definitely should upgrade to 64 bit. Between your two video cards, they are probably using up 3 out of 4 gigabytes of available address space on a 32 bit OS. That probably is why your memory score has lowered in WEI when you have both cards enabled. Upgrading to 64 bit will raise the memory addressing limit much higher, and will allow you to use all of your memory while you have both video cards enabled.