Just to add my possibility superfluous 2 pence, until about 18 months ago I ran an old RME Fireface 800 via FW400 through a PCI adapter and windows 10. It was rock solid, I only got rid because I was moving into my little home studio and wanted something with a volume control for my speakers.
I’d say at this point I wouldn’t put it outside the realms of possibility that an update will break firewire on Windows since it’s really an abandoned standard now, but for the time being it should work.
Actually I’ve just remembered… it was rock solid unless you turned the firewire cable round. Then it went crazy.
What do you mean turned round?
It’s the same connector at both ends - one way round it worked flawlessly, the other way round it glitched like crazy. 
The 1394 6 pin out configuration uses two sets (1 send, 1 receive) of twisted pair differential wires, so it should have not made a difference unless a contact was dirty and made better contact in one direction.
Maybe the electrons were so used to going in one direction they got confused when switched around. 
This is probably irrelevant but I’ve heard directionality can be an issue with grounds in guitar cables? I guess a ground (shield) might not work as well (or not at all) if hooked to a different device. Just a thought.
Oh, it’s all coming back to me now. I had wondered if it was something to do with the ferrite bead which was attached at one end, but the ground thing is a possibility - I actually got a ground loop at around -80db (just loud enough to annoy when present on every input!) until I scraped away some of the powder coating on the computer case so that the bare faceplate of the pci card had a ground connection through the case.
Hey…just tell me if it works! lol
Now I have a question about if this computer below being a good computer for recording (after my other question about firewire and Windows 7 and in the event that my new PCI card fails). Is this computer below a good system for recording? 320 GB seems kind of small now days, is there a way to add a internal hard drive to add more room for music file storage?
2008 APPLE MAC PRO 3,1 2.80 GHz Intel Xeon processor, 4 cores, PCIe slots, 12GBs of RAM , DVD-RW Drive, 320 GB SATA hard drive with Mountain Lion OS X 10.8.5 (w/PT HD10)
Just answered this here:
but yes, these old Mac Pros were infinitely expandable but not with off the shelf components for graphics or sound. The HDD’s can be replaced with SSD’s quite happily though.
This should be the specs for the MAC Pro you are looking at: mac-pro-quad-core
Looks like it has internal expansion bays for additional drives. I’m not a MAC user, but a quad core Xeon should be up to the task of recording, maybe some forum members can chime in.
I’m STILL cranking away on an old 003 FireWire interface and doing just fine. Lol
I would think the quad core Xeon should handle recording fine… comparable to a quad-core i7 but it probably runs a little hotter and sucks a bit more electricity than a ‘modern’ chip.
A few years ago I picked up a refurb HP z420 workstation with a 6-core Xeon E5 1650, 8GB DDR3 RAM, Win-10 Pro with USB3 and FireWire ports for about $450.00. It’s built like a tank, runs great, and has a ton of room for expansion (multiple drive controllers, 8 slots for RAM, etc.) The built in FireWire works fine with my TCElectronic Konnekt 6. I want to upgrade my RAM but I’ve never run into a problem with the 8GB… so I keep putting it off. I should just do it while I still can! 
I’ve worried about the support of my FireWire interface but so far not problems. I would like to pick up a MOTU M2 as it sounds like a bargain. 
So it worked, if anyone even remembers this thread. I was able to purchase a used Universal Audio apollo 8 interface and use the firewire on a Windows 7 machine. The card I purchased off of Amazon was a https://www.amazon.com/gp/product/B002S53IG8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 and it worked. I had to do some downloading of some stuff obviously but I have a clear audio signal path going into my Sonar x3 program and I have recorded myself talking. I just have to figure out how to set up the playback so I can hear it. I can see the sound on the file and I see the meter going up during recording and playback, I just cant hear anything coming out of the headset.
Have fun !!!
really cool! That’s good to know