Ah, thanks guys - serengeor is right; it's the video drivers. I didn't read far enough up, my apologies.
==14969== HEAP SUMMARY:
==14969== in use at exit: 27,758 bytes in 318 blocks
==14969== total heap usage: 3,119 allocs, 2,801 frees, 667,560 bytes allocated
==14969==
==14969== 112 (8 direct ...