Mh, I just tried it out and both are identenical for me:
>>> os.environ'path']
'C:\\Program Files (x86)\\AMD APP\\bin\\x86_64;C:\\Program Files (x86)\\AMD APP\\bin\\x86;C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\;C:\\Program Files (x86)\\ATI Technologies\\ATI.ACE\\Core-Static;C:\\Program Files (x86)\\QuickTime\\QTSystem\\;C:\\strawberry\\c\\bin;C:\\strawberry\\perl\\site\\bin;C:\\strawberry\\perl\\bin;C:\\Program Files (x86)\\MiKTeX 2.9\\miktex\\bin\\;C:\\Program Files (x86)\\SumatraPDF'
echo %PATH%
C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMD APP\bin\x86;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static;C:\Program Files (x86)\QuickTime\QTSystem\;C:\strawberry\c\bin;C:\strawberry\perl\site\bin;C:\strawberry\perl\bin;C:\Program Files (x86)\MiKTeX 2.9\miktex\bin\;C:\Program Files (x86)\SumatraPDF
Did you start the cmd / ST 2 with different user credentials (admin privileges / user privileges)?