So I copied this post from a coworker of mine, Dennis Bottjer.
IIS compression makes a huge difference and it’s an easy batch file to set it up.
How to Enable IIS 6.0 Compression for SharePoint:
Microsoft’s Internet Information Server (IIS) has long support HTTP Compression. However, supporting and implementing compression are two different things. Many settings within IIS are easily configured from the IIS Admin GUI. Unfortunately, enabling and configuring compression is not supported through the GUI and requires editing the IIS Metabase. THe metabase can be edited manually or updated from a command prompt. The commands can be combine into the following script:
REM Turn On Compression
cscript adsutil.vbs set w3svc/filters/compression/parameters/HcDoDynamicCompression true
cscript adsutil.vbs set w3svc/filters/compression/parameters/HcDoStaticCompression true
REM Set Compression to High Level
cscript.exe adsutil.vbs set w3svc/filters/compression/gzip/hcdynamiccompressionlevel "9"
cscript.exe adsutil.vbs set w3svc/filters/compression/deflate/hcdynamiccompressionlevel "9"
REM IIS 6.0 Only
REM cscript.exe adsutil.vbs set w3svc/filters/compression/gzip/hcscriptfileextensions "css" "js" "asp" "exe" "axd" "aspx"
REM cscript.exe adsutil.vbs set w3svc/filters/compression/deflate/hcscriptfileextensions "css" "js" "asp" "exe" "axd" "aspx"
Consider Adding: “ascx”, “ashx”, “asmx” “xml”
Test the various file extensions and compression levels. Perhaps start with a compression level of 7 to 8 or 9 after monitoring CPU utilization. The results of compression can be monitored using Fiddler.