24/96 playback via http://

We're having a few issues getting 24/96 .wav to play smoothly via 
http:// (from a local upnp server)

We're using an atlas http fsys with the following HELIX_FEATURES -

# The basic audio only profile
exec_profile_file("helix-client-audio-all.pf")

# Enable function level linking - reduces code size by approx 30%
project.AddDefines('HELIX_CONFIG_USE_RLINK')
 
# Remove video related stuff
project.RemoveDefines('HELIX_FEATURE_VIDEO')
project.RemoveDefines("USE_XWINDOWS")
project.AddDefines("HELIX_CONFIG_NO_XWINDOWS")
 
# Hopefully fixes MP3 Locker playback
project.RemoveDefines('HELIX_FEATURE_HTTP_GZIP')
project.AddDefines("HELIX_FEATURE_HTTP_MEMCACHE")
project.AddDefines("HELIX_FEATURE_MIN_HEAP")


Our CPU load for http:// playback is approx 55%. Playing the same 
content via local thumbdrive (file://) cpu load is approx 35%. So don't 
think cpu is getting overloaded.

Our raw network throughput is approx 620 kB/s with 24/96 .wav content 
needing 576kB/s (measure using curl <url> > /dev/null). Fairly close to 
the edge but would have though that should be ok.

Is there anything obviously wrong with our feature set or are there any 
HELIX_FEATURES or parameters that would be worth trying or adjusting ?

Also, can someone explain what these features are for -

HELIX_FEATURE_HTTP_MEMCACHE
HELIX_FEATURE_MIN_HEAP
HELIX_FEATURE_HTTPFSYS_MEM_GROWTH_LIMIT


John