John, I do not think that I am out of memory with 640MB. As I said before I can run 2 jobs on the NT machine with 896MB of RAM.

I now suspect that it's a problem with virtual memory and user control of virtual memory on Win98.

(1). Well, when you run two jobs on the NT machine, was the hard drive blinking all the time? (2). My understanding of the virtual memory is the automatic transfer of data between RAM and hard drive. (3). The reason why I said that was, it is likely that you are out of memory on the Windows98, and the virtual memory is not on automatically. On the other hand, the NT machine detected the shortage of RAM and turned on the virtual memory automatically. (4). Does it make sense? Is it possible to know how much memory is still available when the two job is runing on the NT machine?

John, I do not know how PCs use virtual memory since there is plenty of unused memory when I run one job on NT and about about 190MB when I run two jobs. Even when I run only one job, NT uses virtual memory; I do not understand why any virtual memory should be used