Well you probably get no choice but Server 2003 implements a completely different IO scheme and is much better at handling memory and disk IO. As for disk speed 15K SCSI drives on a GOOD RAID controller is going to beat out the SATA drives.
That does not explain though what is causing it to hang and not respond. Slow writes should show up in event viewer as an error.
Enable event logging and it may give you more details.
And this is a stand alone server, not a VPS correct ?
When I'm on your site and it's running fine it seems to be okay speed wise so that leads me to think something else is going on and hanging the system. Maybe it is a hardware issue that locks it up and nothing to do with software.
What type of access do you have to the system when it's running normally? Can you run all the normal Windows tools and get to all the diagnostic tools?
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