Dumb crossfire question

[cdell1234]

Do I need to have the same model of 3870 to run them in crossfire? Or could I run an XFX with an HIS?

EDIT: I read the faq. New Question: I have a 3850 currently. Should I get another 3850 for xfire or should I just upgrade to maybe a 3870 or wait a month or two and get a 4870?

 

[cdell1234]

The 3850 is adequate right now, so I can wait, but my budget will probably be around 150. I just noticed recently crysis started crashing after about 1.5 hrs and the card getting really hot. I suppose if I wait a couple months I may be able to find a 4890 for that price.

This weekend when I was out of town best buy had a sale on 3870s for 40 dollars each, I wish I would have been around to get 2.