you had a bugcheck while ventrilo was running, another while teamspeak was running, another due to key windows memory data structures corrupted. The mapping of virtual memory from your pagefile.sys to the actual location of memory was corrupted.
There can be a lot of different causes for these problems.
you have very many suspect drivers installed that can be the cause.
\SystemRoot\System32\Drivers\SmartDefragDriver.sys Mon Dec 23 02:05:52 2013
any bug in this driver could have caused the problems.
(but BIOS bugs, old driver could be providing errors to the defrag driver)
here is what i would do:
update your BIOS and the new drivers provided on the dell site:
http://www.dell.com/support/home/us/en/04/product-support/product/alienware-x51-r2/drivers
your bios is from 2013, dell just made a june 28 2015 BIOS update and new drivers.
you should pick then new drivers and BIOS update, reboot and retest.
if after the update you still get bugchecks, you can either start removing suspect software drivers.
example:
\SystemRoot\system32\drivers\DDDriver64Dcsa.sys Wed May 28 12:58:54 2014
\SystemRoot\system32\drivers\DellProf.sys Tue Nov 20 06:19:25 2012
\SystemRoot\system32\DRIVERS\hamachi.sys Thu Feb 19 02:36:41 2009
\SystemRoot\System32\Drivers\SmartDefragDriver.sys Mon Dec 23 02:05:52 2013
or you can run cmd.exe as an admin then run
verifier.exe /standard /all
to force windows to check for common driver mistakes and bugcheck if it finds a driver that is corrupting memory.
the driver name will be written in the memory dump file.
Note: use verifier.exe /reset to turn of this extra checking when you are done testing.
this procedure will only help to find a bad driver, it will not check for common hardware errors.
(memory corruption caused by bad BIOS settings,...)