diff -up xf86-video-ati-6.12.1/src/radeon_driver.c.jx xf86-video-ati-6.12.1/src/radeon_driver.c
--- xf86-video-ati-6.12.1/src/radeon_driver.c.jx	2009-04-09 11:40:31.000000000 -0400
+++ xf86-video-ati-6.12.1/src/radeon_driver.c	2009-04-09 11:52:43.000000000 -0400
@@ -3089,6 +3089,15 @@ Bool RADEONPreInit(ScrnInfoPtr pScrn, in
 	    } else if (IS_R300_VARIANT) {
 		crtc_max_X = 2560;
 		crtc_max_Y = 1200;
+	    } else if (info->ChipFamily >= CHIP_FAMILY_R600) {
+		/* no kms, but also no 3d, so be a little aggressive */
+		if (pScrn->videoRam >= 128 * 1024) {
+		    crtc_max_X = 4096;
+		    crtc_max_Y = 1920;
+		} else {
+		    crtc_max_X = 2560; 
+		    crtc_max_Y = 1920;
+		}
 	    } else if (IS_AVIVO_VARIANT) {
 		crtc_max_X = 2560;
 		crtc_max_Y = 1600;