Aspire 5102 IRQ's

I'm fiddling with my oldish 5102 Vista machine to try to work out why firewire works so badly on it and another newer Acer, and have been looking at the IRQ allocations.

I quite readily admit that I'm out of my depth, but maybe someone can explain or even just see if their machine is the same.

Going into Device Manager, View menu and selecting "Resources by Type" gives a big list of IRQ assignments, at the bottom of which are the PCI ones. Here, the firewire controller appears sharing an IRQ with the cardbus slot that holds the pcmcia card that hosts it (not sure this is right or good), and there are two listings for pci-to-pci bridge both with negative IRQ's. When I unplug the firewire pcmcia card, the firewire controller disappears as expected and the bridge and cardbus IRQ's remain the same.

Looking up negative IRQ's on the Microsoft site, I see that these are normal, but only with a pci express bus, which I didn't think this machine had.

So, if anyone else has one of these machines handy, would it be possible to check whether it reports negative IRQ's.

The later Lenovo XP machine that I'm typing this on lists the pci Express bus IRQ's, but they are all normal positive values.