Very slow WMS connection through GIS application

[Ryan Ollerenshaw]

The connection to my WMS server through a GIS application such as uDig or ArcGIS
is painfully slow, Does anyone know what could be causing this?  My dataset is
rather large about 70 high resolution tiles, it seems like whenever I do a pan
or a zoom the GIS application is reloading every tile, is there a way to keep
this from happening?

Thank you and here is my map file incase it may provide some clues as to what I
have done wrong:

NAME WMSDEMO
STATUS ON
SIZE 1000 600
EXTENT 0 -90 360 90
#UNITS METERS
SHAPEPATH "../data"
IMAGECOLOR 255 255 255

WEB
  TEMPLATE test_template.html
  IMAGEPATH "/tmp/ms_tmp/"
  IMAGEURL "/ms_tmp/"
  METADATA
    WMS_TITLE   "WMS_Mars_mapserver"
    WMS_ACCESSCONSTRAINTS "none"
    #WMS_ONLINERESOURCE "http://neuron/cgi-bin/mapserv?map=display.map&"
    WMS_SRS     "EPSG:4326" #"AUTO:42003"
  END
END

PROJECTION
  "init=epsg:4326"
END


LAYER
  NAME "themis"
  STATUS ON
  TILEINDEX "thm_dir.shp"
  TILEITEM "location"
  TYPE RASTER
  DUMP TRUE
  METADATA
    WMS_TITLE "THEMIS_Data"
  END
END
LAYER
  NAME "moc"
  STATUS ON
  TILEINDEX "moc_256.shp"
  TILEITEM "location"
  TYPE RASTER
  METADATA
    WMS_TITLE "MOC_Data"
  END
END

LAYER
  NAME "mola"
  STATUS ON
  TILEINDEX "mola_color.shp"
  TILEITEM "location"
  TYPE RASTER
  METADATA
    WMS_TITLE "MOLA_Data"
  END
END



END # of map file