Arch Linux

Description: gnash plugin is not working : _very_ slow refresh, no sound, no video started even on youtube (which is supported by gnash in a quiet good way).
i am using a i686 kernel, with xf86-video-ati driver up to date, R300 hardware.

Additional info:
* package version(s) : 0.8.4.1
* config and/or log files etc.

My .gnashpluginrc file :
set splashScreen true
set localHost false
set localDomain false
set insecureSSL false
set debugger false
set actionDump false
set parserDump false
set writeLog true
set sound true
set pluginSound true
set ASCodingErrorsVerbosity false
set malformedSWFVerbosity false
set malformedAMFVerbosity false
set enableExtensions false
set startStopped true
set streamsTimeout 0
set movieLibraryLimit 8
set delay 0
set verbosity 0
set solReadOnly false
set SOLSafeDir /dev/null
set localConnection false
set LCTrace true
set LCShmkey 0
set ignoreFSCommand true
set debuglog /home/xglurb/gnash-dbg.log
set documentroot
set flashSystemOS
set flashVersionString LNX 9,0,999,0
set urlOpenerFormat epiphany -remote 'openurl(%u)'
set GSTAudioSink
set whitelist
set blacklist

Some of the outputed log (verbosity = 5)
25752:3059128768] 15:10:03: DEBUG: OpenGL extension version - 1.2
25752:3059128768] 15:10:03: ERROR: Cannot find the double-buffered visual.
Trying single-buffered visual.
25752:3059128768] 15:10:03: DEBUG: Got single-buffered visual.
25752:3059128768] 15:10:03: DEBUG: Created XEmbedded window
25752:3059128768] 15:10:03: DEBUG: void gnash::Gui::resize_view(int, int) enter
25752:3059128768] 15:10:03: DEBUG: returning
25752:3059128768] 15:10:03: DEBUG: Base url set to: http://www.youtube.com/watch?v=qHkWv1vHtHk
25752:3059128768] 15:10:03: UNIMPLEMENTED: SWF9 is not fully supported, trying anyway but don't expect it to work
25752:2886400912] 15:10:03: UNIMPLEMENTED: LanguageCode in DefineFont (2 or 3)
25752:2886400912] 15:10:03: DEBUG: String Arial with length 6 had 1 trailing NULLs, trimmed
25752:3059128768] 15:10:04: DEBUG: Advance interval timer set to 10 ms (~ 100 FPS)
25752:3059128768] 15:10:04: DEBUG: Loading native class MovieClip
25752:3059128768] 15:10:04: DEBUG: get_exported_resource called, frame count=1

Steps to reproduce:
open (for example) http://www.youtube.com/watch?v=qHkWv1vHtHk
Click play if gnash is configured to open as stopped
Refresh starts very slowly, no video playing... just controls/download progression