>>It may not necessarily be the size of the buffer. You are updating the status bar with every write, which may be a relatively slow operation. A larger buffer results in less iterations of writes which in turn means less status bar updates.
>
>As mentioned in the other message, the buffer increased to 256 k made it almost instant.

I think Rob's point was that increasing the buffer size from 4Kb to 256kb would mean your loop count is reduced by a factor of 64.
But is it the loStream.Write() or the loProgressBar.ShowProgress() which is taking the time.....