hi, in general font rendering shouldn't be different in firefox dev edition. could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

Here it is , and i have also attached two screenshots. One with developer and the other with firefox. Font rendering in developer makes the fonts thin whereas the firefox makes it bolder and clearer.

Application Basics

Name: Firefox Version: 39.0a2 Build ID: 20150511004005 Update Channel: aurora User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:39.0) Gecko/20100101 Firefox/39.0 Multiprocess Windows: 0/1 (default: false)

Crash Reports for the Last 3 Days

All Crash Reports

Extensions

Name: ADB Helper Version: 0.7.4 Enabled: true ID: adbhelper@mozilla.org

Name: Bluhell Firewall Version: 2.5.1 Enabled: true ID: {6BB5760D-F97E-421B-AF5B-8457A90C3CED}

Name: Logitech SetPoint Version: 6.5 Enabled: false ID: {F003DA68-8256-4b37-A6C4-350FA04494DF}

Graphics

Adapter Description: Intel(R) HD Graphics 4000 Adapter Drivers: igdumdim64 igd10iumd64 igd10iumd64 igdumdim32 igd10iumd32 igd10iumd32 Adapter RAM: Unknown Asynchronous Pan/Zoom: none Device ID: 0x0166 DirectWrite Enabled: false (6.3.9600.17415) Driver Date: 5-16-2014 Driver Version: 10.18.10.3621 GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC) Subsys ID: 194d103c Vendor ID: 0x8086 WebGL Renderer: Google Inc. -- ANGLE (Intel(R) HD Graphics 4000 Direct3D11 vs_5_0 ps_5_0) windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0

Important Modified Preferences

browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.smart_size.first_run: false browser.cache.frecency_experiment: 1 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.sessionstore.upgradeBackup.latestBuildID: 20150511004005 browser.startup.homepage_override.buildID: 20150511004005 browser.startup.homepage_override.mstone: 39.0a2 dom.mozApps.used: true extensions.lastAppVersion: 39.0a2 gfx.direct3d.last_used_feature_level_idx: 0 media.gmp-eme-adobe.lastUpdate: 1431439729 media.gmp-eme-adobe.version: 9 media.gmp-gmpopenh264.lastUpdate: 1431439730 media.gmp-gmpopenh264.version: 1.4 media.gmp-manager.buildID: 20150511004005 media.gmp-manager.lastCheck: 1431439727 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.history.expiration.transient_current_max_pages: 104858 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true privacy.sanitize.migrateFx3Prefs: true

Important Locked Preferences

JavaScript

Incremental GC: true

Accessibility

Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.8 Version in use: 4.10.8

NSS Expected minimum version: 3.19 Basic ECC Version in use: 3.19 Basic ECC

NSSSMIME Expected minimum version: 3.19 Basic ECC Version in use: 3.19 Basic ECC

NSSSSL Expected minimum version: 3.19 Basic ECC Version in use: 3.19 Basic ECC

NSSUTIL Expected minimum version: 3.19 Version in use: 3.19

Experimental Features

You can try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

You need to close and restart Firefox after toggling this setting.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes
• https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

I have tried that but nothing changed . Maybe this is they way developer edition has to be . Maybe it uses a developer font which makes rendering look different . It reminds me the rendering on linux machines.

I have found the culprit . It is the experimental feature of Enable Multiple Processes of firefox developer edition .once enabled the rendering of the fonts goes bad. So there is a bug with that feature

I have the same issue.

@shak3800 I wanted to disable Multiple Process option as you said it is buggy. But it was disabled already. [Enable multi-process Firefox Developer Edition (disabled: An accessibility tool is or was active. See bug 1115956.)]

Nevertheless it is disabled, i have this issue with fonts yet.

Any idea? :(

[+] Chromium-based browsers and Firefox Developer font render screenshots attached for more info.