User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0b10) Gecko/20100101 Firefox/4.0b10 Build Identifier: ff4.0beta10 Firefox 4 beta 10(it was also in 9) UI works slowly in Windows 7 with Basic theme(that means Aero is disabled) You can see this wheh using main menu(wnen going through main menu items you can see how previous menu slowly dissapears and next showes- they both can be present in the same moment), link field, "save password dialog", etc FF has no addons installed(only Feedback 1.0.4 and no matter is it enabled or no) Bug not present when using Safe Mode(in the same time i have no addons installed) Reproducible: Always Steps to Reproduce: 1.Use Windows 7 2.Disable Aero theme(choose basic Theme) 3.Just use Firefox4
If you start in regular (not safe) mode but turn off hardware acceleration in preferences, do you still see this issue?
Setting gfx.direct2d.disabled to "true" fixes slowness. And in the same time at config:support page: Direct2D enabled changes from "true" to "false" DirectWrite enabled changes from "true" to "false" GPU Accelerated WIndows changes from "1/1 Direct3D 10" to "1/1 Direct3D 9"
In the same time according to: http://www.club-3d.com/index.php/products/reader.en/product/37.html my videocard supports DirectX® 10.1 and Shader Model 4.1
Firefox 4.0b11 about:support sayes: Direct2d Enabled = Blocked for your video card driver DirectWrite Enabled = False GPU Accelerated WIndows = 0/1 Seems it was fixed by some of commits, related to Bug 623338.