I've searched quit a bit and have yet to find someone experiencing identical or near identical circumstances that I am facing.
I've installed SLI and crossfire before without issues.... My computer was working fine until I installed a second 5770 in crossfire. Once seated in the mobo, I fired up my computer. I booted into Windows without an issue. I was on ATI 10.7 drivers at the time. The screen started to flicker, had lines, and tearing across both monitors. The flickering and lines stayed on my left monitor.. The right monitor looked fine and I could see the mouse cursor scrolling. Eventually, my computer locked up after 1 min and I had to hard reboot. The same scenario happened again... and I rebooted again. The 3rd time logging in, everything seemed stable... both monitors displayed correctly... so I thought I was out of the woods. I proceeded to overclock with auto-tune... and restarted my computer to get ready to play Starcraft 2 with a couple friends.
Once I logged back into my computer, the same tearing, flickering, and lines started again on my left monitor. At first, the monitor would look fine. If I opened a window or right clicked the desktop, this would set off the problem listed. Also, during the 3rd attempt... windows kicked back an error stating there were problems with the display driver. My screens dimmed quite a bit.
Thinking this was a driver issue, I restarted into safe mode. I uninstalled and deleted the display drivers and for both listings of the HD 5770 in device manager. I logged back into windows without an issue (and without display drivers) and proceeded to uninstall everything ATI including CCC. After this was complete, I rebooted, logged in, and proceeded to AMD.ATI to download the 10.8 drivers. I reinstalled and ran into the same tearing, flickering, and line issue. This is where my head hit the brick wall... and I'm wondering if I don't have a motherboard issue... but the slots are registering both ATI 5770 cards.
Please see all background information below... I tried to be as detailed as possible. Yes, I have the crossfire connector seated on both cards. Both monitors work fine through my KVM on other PC's... I have 3-4 PCS hooked up to it. They work outside the KVM as well... but for all purposes here, I do have this computer hooked up through a KVM.
+ My computer didn't experience the issue before I installed the 2nd 5770 and crossfired
+ OS: Windows 7 Pro 64Bit
+ Computer was Built (all new parts from newegg.com) during the 1st week of June 2010.
+ All bios and chipset drivers are up to date
+ I tested ATI drivers 10.7 and 10.8... the same issue exists with both.
+ This computer is used for gaming and virtual machines... the build is pretty fresh. No other graphic cards were used in the pc... and only the parts listed were used in the pc.
+ I am currently working through the infamous x58 RAM issue with ASUS and Patriot... they are trying to figure out where the issue is. only 8 of 12 Gigs of ram register. The other night... 12 of 12 registered. This is why I state... maybe I have a motherboard issue.
+ NO overclocking has been done to the RAM or Processor outside setting 1600 & 3200 for the ram in the BIOS.
+ (1 qty) SAPPHIRE 100283L Radeon HD 5770 (Juniper XT) 1GB 128-bit GDDR5
+ (1 qty) Antec TPQ-850 850W Continuous Power ATX12V / EPS12V SLI Certified CrossFire Ready
+ (1 qty) Intel Core i7-930 Bloomfield 2.8GHz LGA 1366 130W Quad-Core
+ (1 qty) ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner
+ (1 qty) Samsung Blu-ray Drive
+ (1 qty) ASUS P6X58D-E LGA 1366 Intel X58 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
+ (2 qty) Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM SATA 6.0Gb/s 3.5" Internal (RAID 0)
+ (2 qty) G.SKILL Ripjaws Series 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory
+ (1 qty) Antec Nine Hundred Two Black Steel ATX Mid Tower Computer Case
+ (2 qty) Dell 27" Ultra Sharp monitors
+ (1 qty) LINKSKEY LDV-DM704AUSK 4-Port Dual Monitor (DVI+DVI) 7.1 Surround Sound
Items I still need to test (ran out of time last night):
1.) test 5770 card #1 in PCIE slot #2 by itself. I know card #1 works.
Any thoughts? I ran memtest86+ and that returned no errors. CPUz registers all ram, sees the processor and all information. CCC shows the crossfire... and it recognizes both cards. Windows device manager shows no issues with drivers.
I also used both monitors directly to the original 5770 card (dual monitor setup) without ANY issue.
You're best bet is to do what you already suggest. Take the new 5770, test your old one in the SAME slot its in (make sure it didn't start fussing up). If you don't have any problems, put the old 5770 in the second slot, see if you have any problems. If you DON'T have any problems, try the new 5770 in the first slot.
ok... I took both cards out. I put card #1 (original) into PCIE slot #2 (after uninstalling all ATI drivers and software). I fired up the computer and reinstalled ATI 10.8 drivers. Everything worked ok.
I proceeded to uninstall the ATI drivers again and put card #2 into PCIE Slot #1. I installed ATI 10.8 drivers... and started getting the same issues as experienced with the 5770's in Crossfire.
However, I didn't uninstall the drivers... took out card #2 from PCIE slot #1 and re-inserted card #1 into PCIE Slot #1... and encountered the same issue as I did in Crossfire. I uninstalled the drivers and re-installed the ATI 10.8 drivers. Everything is working perfect with card #1. I'm going to RMA the 5770.
Maybe it was obvious... I wanted to throw the issue out here in case there was something I was missing. Now if I can get the x58 memory issue to pan out...