diff -up xf86-video-ati-6.7.196/src/radeon_driver.c.jx xf86-video-ati-6.7.196/src/radeon_driver.c
--- xf86-video-ati-6.7.196/src/radeon_driver.c.jx	2008-01-15 17:11:38.000000000 -0500
+++ xf86-video-ati-6.7.196/src/radeon_driver.c	2008-01-15 17:11:53.000000000 -0500
@@ -2903,8 +2903,9 @@ _X_EXPORT Bool RADEONPreInit(ScrnInfoPtr
 	    crtc_max_Y = 1200;
 	} else {
 	    if (IS_R300_VARIANT || IS_AVIVO_VARIANT) {
-		crtc_max_X = 2560;
-		crtc_max_Y = 1200;
+		/* not the max, just egregiously large */
+		crtc_max_X = 2560;
+		crtc_max_Y = 1600;
 	    } else {
 		crtc_max_X = 2048;
 		crtc_max_Y = 1200;