Assuming it's modern Windows installations, one way to !potentially! speed things up would be this - Microsoft's System Information will allow you to connect to remote computers (as long as you haven't disabled the WMI service on them - and as long as you are signed as someone with an account that has permissions on the workstation) and will allow you to view the same kind of information that you can view if you were on the system running it directly from the console. (I run it from a system where I'm signed in as the domain administrator).
This will allow you to determine how much memory is installed - and while it won't tell you specifically which motherboard is in the system generally, from the manufacturer information, model, and the BIOS information reported, if you have any kind of standardization at all it should be pretty easy to know which one's in which.
<S>
P.S. I'm assuming you are using a domain architecture - I can't see it working very well if you are using a Workgroup(s) format.