Now:
             total       used       free     shared    buffers     cached
Mem:          7.7G       5.7G       2.0G       663M        16M       959M
-/+ buffers/cache:       4.8G       3.0G
Swap:         1.0G       1.0G        14M

Right before it froze for a few seconds (manually rewritten from recording):
             total       used       free     shared    buffers     cached
Mem:          7.7G       7.6G       152M       988M       404K       1.0G
-/+ buffers/cache:       6.6G       1.2G
Swap:         1.0G       1.0G         0B
Right after it un-froze:
             total       used       free     shared    buffers     cached
Mem:          7.7G       5.6G       2.1G       640M       8.1M       781M
-/+ buffers/cache:       4.8G       2.9G
Swap:         1.0G       1.0G        80K