GPS Statistic Differences

I recently received a Garmin eTrex 20 for my birthday. I used it a few weeks ago to record a track of my hike up Lower Wolfjaw. I cleaned up the track (got rid of all the sqiggles where we stopped) and have been looking at the track in both the Garmin Basecamp software and Google Earth. I noticed that some of the stats the two programs give me for the hike are very different even though I'm using the same exact file in both (some stats do match up)



Below are some examples of what matches and what doesn't (E - Google Earth and B - Garmin Basecamp)

• Time
  
  E - 10h 10m 34s
  
  B - 10h 10m 34s


• Distance
  
  E - 9.4 miles
  
  B - 9.6 miles


• Average speed
  
  E -0.9 mph
  
  B -0.9 mph


• Max speed
  
  E - 3.6 mph
  
  B - 9 mph


• Min elevation
  
  E - 1264 ft
  
  B - 1279 ft


• Max elevation
  
  E - 4165 ft
  
  B - 4197 ft


• Elevation gain
  
  E - 3263 ft
  
  B - 4228 ft


• Elevation loss
  
  E - 3264 ft
  
  B - 4212 ft

Does anyone have any explanations as to why the data is so different? The only thing I could come up with was for the elevation discrepancies. I'm thinking maybe the Basecamp elevations are based on what my GPS recorded and the Google Earth elevations are based on the data/topo maps? In that case which is more accurate? And that doesn't explain the distance or max speed differences