G450 video memory query

I have Millenium G450 dual head 16Mb cards fitted to my PCs.

I use the cards in 'single' monitor mode.

My question is all 16Mb of memory available to the allocated single
monitor, or is it only 8Mb because it is a dual head card?

I'm not able to run a piece of software that requires 16Mb of video ram
on my XP computers, and I am wondering if upgrading the machines to
32mb G450 cards will resolve the problem, otherwise I will reluctantly
have to ditch the G450s and buy some budget MX4000 cards.


bill