PerPanicz said

Problem have just started yesterday from no reason. I've tried everything to fix this. Reinstall, cleaning profile folders etc. It helps, but only for a short time (about 15 minutes), then fonts are weird again, with no smoothing and not bolded when they should be - not proper in one word. If I don't close Firefox I have the good ones, but after relaunch, fonts are messed up. All of my fonts are not corrupted (tested in Word), other programs are working fine, including other webbrowsers, but I don't like them too much. I'm using Developer Edition of Firefox right now, but standard version have same problem. It's not a plugin fault too. I'm using only Adblock and problem is still there without it. My OS: Windows 10 Pro (x64). It's a little bit chaotic, but picture explain everything. http://s18.postimg.org/fg9n22kzd/ffff.png - comparison At the top is the right one, at the bottom messed up. http://s28.postimg.org/bwise10q1/ff3f3.png - this is how looks button on this site after problem began. You can see by yourself it's different.

http://s24.postimg.org/dga0meumd/fff3f.png - there you can see better font failure

Can you check whether your various installations of Firefox are using hardware acceleration or not when this goes haywire? On the support information page, there is a Graphics table which should have that data point.

To launch the page,you can use either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Then look for GPU Accelerated Windows.

jscher2000 said

Can you check whether your various installations of Firefox are using hardware acceleration or not when this goes haywire? On the support information page, there is a Graphics table which should have that data point. To launch the page,you can use either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Then look for GPU Accelerated Windows.

For Developer Edition: 1/1 Direct3D 11 WARP (OMTC) 40.0: 1/1 Direct3D 11 (OMTC) And I've checked 40.0 on new profile, so fonts were still fine.

It's hard to think of what might change by itself after 15 minutes, or in a new profile after exiting and starting Firefox again. My only thought was your graphics card possibly being on an updated block list that was getting downloaded and applied, but if hardware acceleration is on both before and after things go wrong, then that's not it.

jscher2000 said

It's hard to think of what might change by itself after 15 minutes, or in a new profile after exiting and starting Firefox again. My only thought was your graphics card possibly being on an updated block list that was getting downloaded and applied, but if hardware acceleration is on both before and after things go wrong, then that's not it.

It has to be something with this WARP thing. After deleting profile and restarting Firefox Developer Edition there's no WARP in GPU Accelerated Windows, just 1/1 Direct3D 11 (OMTC).

Warp GL was enabled in Firefox 37, but maybe there is a Windows 10-specific glitch. To try disabling it:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste layers and pause while the list is filtered

(3) Double-click the layers.d3d11.disable-warp preference to switch it from false to true

(I don't know whether that takes effect immediately or after a restart)

jscher2000 said

Warp GL was enabled in Firefox 37, but maybe there is a Windows 10-specific glitch. To try disabling it: (1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful. (2) In the search box above the list, type or paste layers and pause while the list is filtered (3) Double-click the layers.d3d11.disable-warp preference to switch it from false to true (I don't know whether that takes effect immediately or after a restart)

Sadly it didn't work, but I saw on the Developer Edition that Direct2D isn't working. It says it's blocked for actual driver version, but on normal version everything is fine. And I can even say, there's no problem with fonts, because I didn't synced this time with my account, so settings are default. Is it possible that Direct2D cause a problem?

Damn, it's pretty hard to talk about it, when I'm not good enough in English.

Edit: Alright. It HAS to be Direct2D. After restarting the 40.0 version of Firefox it says now that Direct2D it's blocked, but just a minute ago (before I've closed Fx) it was fine and fonts were displayed correctly.

Thank you for researching that. I don't know that anyone has updated their Windows 10 drivers yet, or whether Microsoft allows you to install from OEM sites instead of Windows update. So much to learn about Windows 10...

So only solution is to wait for fixed drivers? A lot of people complaining about newest Nvidia drivers made SPECIALLY for Windows 10 release, but there's no hotfix on sight.

See this bug report for the reason behind blocklisting the Nvidia driver:

• bug 1189940 - Win10 crashes in nvwgf2um.dll@0x47c5d via CompositorD3D11::EndFrame

Please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html

Alrighty then. I have to wait for a hotfix, but it's kinda sad, because I had no crashes with 353.62 drivers. Thank you all for help.

Looks like the block list was reversed.