Suggested Systems

Run tests once with the latest GPU driver available and a second time with whichever older driver version you have access.

System	Platform	CPU	GPU
Centurion	Windows 7 Ultimate 32-bit	Intel Core 2 Duo 2.4 GHz	nVidia GeForce 8800 GTS 640MB
Frostmane	Windows XP Professional SP3 32-bit	AMD Turion64 X2	ATI Radeon Xpress 1100 128MB (shared)
Higgins	Windows 8 Professional 32-bit	Intel Core i7-2620M	Intel HD Graphics 3000 1720MB (shared)
Jandice	Windows 8 Consumer 64-bit	AMD FX-8120	AMD Radeon HD7670 1024MB
Lothar	Windows 8 Professional 64-bit	Intel Core 2 Duo 2.13 GHz	nVidia GeForce 7300LE 256MB
Mango	Windows Vista Basic 64-bit	Intel Core i7-920	ATI Radeon HD4850 512MB
Marwyn	Windows 7 Home Premium 64-bit	AMD Phenom II X4	ATI Radeon HD3450 256MB
Palpatine	Windows XP Professional SP3 32-bit	Intel Core 2 Duo	nVidia GeForce 8800 GTX 768MB (x2 in SLI)
Setesh	Windows 7 Home Premium 64-bit	Intel Celeron 900	Intel GMA 4500 1700MB (shared)
Shadowsong	Windows Vista Home Premium 32-bit	Intel Pentium D 2.8 GHz	Intel GMA 950 256MB (shared)
Silvermoon	Windows XP Professional SP3 32-bit	Intel Core 2 Duo	Intel GMA 950 256MB (shared)
Zito	Windows Vista Ultimate 32-bit	Intel Core 2 Duo 2.5 GHz	nVidia GeForce 8600M GT 256MB

Instructions

Download https://ftp.mozilla.org/pub/firefox/nightly/latest-mozilla-aurora/firefox-40.0a2.en-US.win32.installer.exe
Run installer and select customize
Put the install in a known directory (C:\Aurora for purposes of this example)
Do NOT allow it to launch Firefox at the end of the install

Open C:\Aurora\defaults\pref\channel-prefs.js in a text editor
Change the line reading pref("app.update.channel", "release"); to pref("app.update.channel", "foobar");
Save and Close the text file

Run cmd.exe
Change directory to the folder where you installed Firefox: cd C:\Aurora
Run firefox.exe: firefox.exe -P -no-remote - This will bring up our profile selector window.
Use the "Create Profile" button to create a profile new profile
Once the profile is created, select it, and then click "Start Firefox"

Play one of the game demos for 15 minutes, keeping an eye out for visual/audible/control issues and crashes.
if you hit an issue with e10s on, retest the demo with e10s disabled
if you hit an issue with e10s off, retest the demo in Chrome
file bug reports for issues that only reproduce in Firefox with e10s on
be sure you're retesting from scratch (assets are cached on first run)