Excellent, but not very relevant to the discussion. My initial question was only to see if pairing a 2gb 5870 with 1gb 5850 was possible and of any benefit.
After I got a no-go for that question, my only question was to the person giving me suggestion to buy another 5850 to crossfire with my existing one (both 1gb) over using just a single 2GB 5870, for the reasoning behind that suggestion. That's it
I am well aware of cross fire performances when two identical cards are concerned. I hear your point that two lower end cards together can outperform a higher end card. But since memories here were different (2 x 1GB) vs (1 x 2GB), I wanted some clarification.
Thanks to you though for your responses. Learning something new everyday.