I have 2 systems, both have FW1884's attached.
In the office; Win7x32 consequently both X1d Expanded and X2a Producer are x32 (really x86).
FW-1884 is the i/o and control surface.
X1 DEFINITELY boots quicker and loads the same project faster, I just tested it.
The Studio specs are in my sig below.
X1d Expanded x32 and X2a Producer x64.
The FW1884 is used only as a control surface, I've gone RME UFX for i/o.
It does "seem" that X2a is a little slow booting and loading projects.
I was kind of blaming this on the iLok 2, but maybe that's not the case.
IF the firewire led is lit on the FW, Sonar should see just fine.
I keep the Studio at 60 degrees this time of year, and the FW can be a bit flakey on initial boot.
There used to be endless threads about the FW having to "warm up".
There is a service bulletin to that effect, and I see it at low temps.
Tom