Ok so perhaps this is an abuse.
W7 32b 6G RAM 4 x 1Tb local SATA disks.
Return from holiday, 422 files, (24Gb) of AVCHD dagged into VRD with the aim of making one file.
Joiner plows through to about 130 files then goes Out of Memory.
However if 100 files are dragged in, then click close in...