This appears to be a growing problem. I finally decided to test out some new drivers and ran into the same exact issue as OP and MrBicce. I see a commonality of the same monitor with at least one of us. Switching to DVI did not resolve my problem, however.
I already reported this in a support ticket to AMD (8/30/13) and have not received a response at all.
- 2x MSI R6870 Twin Frozr II Radeon HD 6870 1GB 256-bit GDDR5 (Crossfired)
AMD Catalyst Driver Version, and Driver History
- WHQL 13.4, 13.9, Beta 13.8, 13.10 2560x1440 NOT AVAILABLE
- WHQL 13.1 2560x1440 is available. Generic Windows drivers also have 2560x1440.
- W7 x64 SP1
- WHQL 13.4, 13.9, Beta 13.8, 13.10 will NOT display 2560x1440 on Asus PB278Q with either HDMI 1.4 or dual-link DVI cabling on primary card (with or without secondary monitor attached). WHQL 13.1 will display 2560x1440 with either HDMI or DVI (with or without secondary monitor attached). Have tried with and without Crossfire.
Motherboard or System Make & Model
- GIGABYTE GA-EP45-UD3P LGA 775
- CORSAIR Enthusiast Series CMPSU-650TX 650W
Display Device(s) and Connection(s) Used
- ASUS PB278Q via HDMI 1.4
- Samsung PN42B450 42-Inch 720p Plasma HDTV (via DVI > HDMI cable)
Applications and Games
- Windows desktop, all games, all applications
- Intel Core2 Quad Q9400 @3.2GHz (2.66GHz) Heatsink: Xigmatek HDT-S963
System Memory Type & Amount
- Mushkin Enhanced Blackline 8GB DDR2 1066 996599
- Primary HDD (boot): Western Digital VelociRaptor WD3000HLFS 300GB 10000 RPM SATA 3.0Gbps
Secondary HDD: Mushkin Enhanced Chronos MKNSSDCR120GB 120GB SATA III SSD
Tertiary HDD: Western Digital My Book Essential 2 TB USB 3.0 (via Buffalo Technology DriveStation SuperSpeed USB 3.0 PCI Express adapter)
Edit: Finally fixed it!
I'm not really certain what did it, but 2560x1440 is now working under 13.10 betas. Somewhere along the lines of uninstalling drivers, rebooting in safe mode and clearing temporary files, cleaning registry keys, check monitor.sys for an update (none), installing ASUS Multiframe, redownloading a fresh driver pack, and reinstalling it got it working. So weird. >.<
11:09 AM by