Quote Originally Posted by overthere View Post
That is my understanding as well, i.e., Fusion-io provides their own OS device driver which "manages" their PCI card.

I believe that their OS device driver also requires "sufficient" system RAM to operate (at least according to the "Windows User Guide" for their ioXtreme version).

This makes me wonder about the extent, if any, to which their OS device driver uses this "required" system RAM as a cache, which has obvious performance (as well as other) implications in addition to the system CPU utilization considerations.
Regarding RAM usage, I have not been able to test this. The manual says that at worst case scenario, when writing in 4KB blocks, the iodrive can use up to 425MB of ram. Using IOMeter my RAM usage is static no matter what I do. Perhaps it is permanently reserved in some way. If someone thinks of a good way to test this then I will gladly do it.