Explorer.exe is occasionally shooting up to using 6 GB of RAM when I'm organizing my files. Its doing this on my laptop, which lags the whole system for obvious reasons.

Specs of laptop:
Windows 8 Pro x64
8 GB 1333 MHz DDR3
ATI Mobility Radeon HD 5650 1 GB
Intel Core i7 740 QM
500 GB 7200 RPM SATA-II HDD

Any ideas what might be causing this?