Still fairly new to the computer world, but i am looking to double up my grafics cards, will these two play nice together. I got the first one on a sale and its not avaliable anymore, the second one is the only i can find that matches it
XFX HD-577A-ZNEC Radeon HD 5770 XTreme Edition 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support
They are both 5770 1GB cards so they will work perfectly together. Crossfire also works with dissimilar model cards from the same series. For example a 5850 and a 5770. Although, sometimes mixing models doesn't always give the best yield in performance. You can Crossfire 5xxx cards with other 5xxx card, and 4xxx cards with 4xxx cards, but not mix them.
(2) 5770's perform as good and most times better than a 5850.