I have an MOTU 896mk3 Hybrid that has USB and Firewire connectivity.  As reported on an older thread here I had issues with this device and USB 3.0 ports and finally resolved that problem with a USB 2.0 port.  Out of curiosity, I picked up a Firewire cable to test with.  I don't have a T.I. Firewire chipset in my PC which kept me from using Firewire initially.  The port on the motherboard is a "VIA 1394 OHCI Compliant Host Controller".  I have no idea what the actual chip version is.  Surprisingly, the 896mk3 Hybrid works on Firewire with the VIA controller on the motherboard.  It will work at  96 Samples per buffer setting, but I get dropouts at 64 Samples per buffer.  It will work at 64 samples with USB (the lowest setting available). 
 
I haven't tried any recording using Firewire, just playback to see if/how it worked.   The Windows 10 1394 driver is the default driver, not the "legacy" driver that I remember having to use in Vista/Win 7 (when I had a Saffire Pro 40 that was Firewire).

MOTU units are pretty forgiving with the Firewire controller.
That said, with a TI chipset controller... you should be able to use that unit at a 64-sample ASIO buffer size.
My 896HD was rock-solid at a 64-sample ASIO buffer size.

It surprised me as an Alesis IO26 and the Saffire Pro 40 wouldn't even connect to anything other than the T.I. controller.  Back in the Vista days the Firewire port (controller) I had was  built into a SoundBlaster interface unit and the IO26 wouldn't connect at all with whatever was in the SoundBlaster (it was not identified).  I bought the Saffire Pro 40 as I needed more analog channels and it was the same way, it wouldn't connect (that was with an old Dell Dimension E510).  I built a new PC with an Intel DP35DP board that had the T.I. chipset and both units worked OK.  When I built the PC I have now, I went with a USB interface unit since it didn't have a T.I. chipset (and the Saffire Pro 40 had hardware problems).
 
Both the IO26 and the Saffire Pro 40 use DICE (the Saffire Pro 40 uses a DICE II) Firewire chipsets, I haven't seen any info on what is in the MOTU.
 
I'll go back to using USB 2.0 but at least I know I could use Firewire if needed, and not everything "must have" a T.I. chipset port in the PC.
 

When you guys say 64 sample buffer are you using this buffer size for both recording and mixing or just recording. I can't see mixing with plugins etc. with such a low sample rate.

That is the sample rate set in the MOTU, not the buffers in Sonar.

fireberd, I'm using my Motu 828mk3 with a VIA pcie card which has the TI chip and most likely yours has a TI chip to.
I am curious about how you guys have your buffers setup. I just got my Motu828mk3 last week so I'm still learning how to use it. In the Motu audio setting you can select sample rate, sample per buffer etc. You guys are able to run your Motu at 64 samples per buffer?  What sample rate are you using.? Do you change the sample per buffer when mixing? The cuemix thing is a little confusing so if there is a good show how to tutorial you know of please let me know.

My VIA is an actual chip on the motherboard, not an add in card. 
I can't run at 64 with Firewire (at least mine with the VIA chip), 96 is as low as I can go.  I get dropouts at 64 with Firewire.  However, with USB 2.0 connection I'm solid at 64.
 
The Cuemix was very confusing for me at the start.  So much that I returned the first 896mk3 Hybrid that I got because of it.  After I sent it back I ran into a customer at Guitar Center who was using MOTU and volunteered to give me some orientation on Cuemix at his studio.  That cleared a lot up for me and if I would have had that opportunity at the beginning I wouldn't have sent the unit back.  After I got the second one I had a question on whether the preamps could be bypassed (they can by using the TRS inputs) and queried MOTU support about that.  Talking to the guy I commented on the Cuemix and he said if I had contacted them he could have helped me with it.  I don't use all the available features but I know they are there if I ever did.