So I have two Sapphire HD 7770 GHZ Edition cards (Crossfired). About 6 months ago my computer started showing them as R7 200 cards. I didn't really pay any mind since there was no performance issues. One of my cards died and I purchased a identical replacement. Now my system shows that I have 1x Sapphire HD 7770 GHZ Edition card and 1x R7 200 card. It allows them to crossfire but it is wreaking havoc with my system. I can't games to load and when I do they are so laggy, it's not funny. When I run the single that identifies as a R7 200, it performs fine, I run the one that identifies as 7700 it seems a little slower. If I cross fire them together forget it. Is how the system recognizes the cards effecting their ability to Crossfire properly? Like I said I bought an identical replacement card. No, I did not pull the wrong card, the one I pulled is dead and won't run on it's own. Thanks.
The R7 250X is a rebranded HD 7700 Ghz Edition, that's why it shows a different name, though both of them should show as the same unless one isn't, and that'd explain why it seems slower, so no the displayed name is meaningless. Take out one at a time and run Furmark for about 30 minutes, see if there's a problem.
You do need to think about replacing them though, the RX 580, which can FINALLY be found sub $200 on sale, is over 300% faster than the 7770GE/250X, and over twice as fast as two in Crossfire assuming perfect 100% scaling, which never happens.