Adrian
I-RAM is not the same as windows ram disk. Using windows ramdisk will not give the same performance increase. There are a number of reasons for this but the main one is that the i-ram is a SATA drive and the SATA infrastructure and SATA windows drivers are designed to be high bandwidth (1.5Gb/s data transfer rate).
The PC I am using is a dual core AMD running XP 64 and 4 G of RAM.
The project is a SOPC targetted at a Cyclone 3. I ran SOPC builder to build the SPOC system and then a VHDL wrapper to connect to the outside world.
I am using Quartus 2 version 8
I am away for 2 weeks but I will compile the project from i-ram and from regular harddisk and get the respective compile times for the various sections when I get back.