Haven\'t tried it myself, but it sounds about right:
The vcache = 65536 setting means 25% of 256Mb ram. So you load up to 78% of memory with samples, while the other 25% is being used to cache disk accesses.
So, the lower you set vcache, the more ram becomes available to GSt for use. It does seem that the GSt indicator reflects the percentage of total memory in your system (which is rather nice, imho).
(Hehehe, its probably only in the PC world where you find that 78% + 25% = 100%, and that is probably what is causing the crash. Its probably because GSt now tries to lock more pages in memory than is available).
It seems that GSt does tend to freeze / crash / slow system to an absolute crawl when you run out of memory. A number of people have experienced this, myself included. Not so nice - maybe some refinements could be made to have it \"gracefully exit.\" Although this is probably as much due to Windows memory managment (or lack thereof), than anything Nemesys could do.