> I don't understand the reason for the huge timing difference. > I have tried defragging the drive first. > I have even tried overwriting an existing file, after defragging. > Is this just the nature of drives, does seek time kill me? > Still seek + latency should be around 10ms + 5ms? Way less than > 150ms. > Do the Win32 write API's suck? My experience is that Windows services and assorted background processes can grab system resources at inconvenient times. I have an ATI video card I use for video capture, and I try to make sure nothing significant is running if I'm grabbing video, else it drops frames. See what task manager shows, and try shutting down everything non-essential (e.g. web servers, ant-virus, Outlook ...), then run the tests again. James