Had to RMA my Sapphire 4870x2 due to it overheating. I did a full format and Win7 reinstall and used the latest drivers for everything. However, with the new card I'm getting constant freezes which forces me to reboot. Sometimes I get a black screen and the fan on the vid card goes to max or sometimes the screen just freezes (though I can still hear sound). It doesn't appear to be overheating (I monitor Catalyst Control Center and it's staying below 60 C will playing Civ 5). I bought a cheap Diamond 4350 vid card to use while I was waiting for the RMA and have had no freezing issues after swapping out the new card for this one even while playing Civ 5.
Could this be a PSU issue? Insufficient power? Thanks! Below are my system specs...
1 x GIGABYTE GA-EX58-UD5 LGA 1366 Intel X58 ATX Intel Motherboard
1 x SAPPHIRE 100251SR Radeon HD 4870 X2 2GB x
1 x SILVERSTONE ELEMENT ST85EF 850W ATX12V / EPS12V S PSU (1 year old)
1 x Intel Core i7-920 Bloomfield 2.66GHz LGA 1366 130W Quad-Core Processor BX80601920
1 x OCZ Platinum 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Memory
1 x Western Digital Caviar Black WD1001FALS 1TB 7200 RPM Hard Drive -Bare Drive
1 x Western Digital VelociRaptor WD3000HLFS 300GB 10000 RPM Hard Drive -Bare Drive
1 x LG Black Super Multi Blu-ray Disc Burner & HD DVD-ROM Drive SATA GGW-H20L
1 x AuzenTech AZT-FORTE X-Fi Forte 7.1 Low Profile PCI Express Sound Card
I had an issue very similar to yours, and it turned out to be my motherboard. It used to work, and then started acting up. I swapped in an older card and it was find, and the card I thought was the issue ended up being fine as well (ran fine in another machine).
Now the previously suspected video card is in another setup and is running like a champ.
I've read about a few others having the issue when the power to the motherboard and/or video card wasn't seated properly, or the 20-pin adapter they were using was at fault.
Thanks for all the responses! Sapphire claims that the diagnostic test on the card that they did before sending it to me showed nothing wrong but I'm dubious. Judging by the wear marks on the card it's obviously a refurbished card but to be sure I guess I need to find another computer to test it in.