Not sure why no one from RME has responded to the question about whether or not the issue Matthias mentioned about multiple Firefaces with the 3.xx drivers has been fixed yet, but because my location recording is tomorrow I changed the drivers and tried it.  No luck.  I was only using two of my three firefaces and it did not even see the second one.  Up until now I have had no more problems with my Windows 7 x64 installation than I did with XP except the firewire dropping out issue that microsoft has a hotfix for.  I installed the hotfix and it appears to be fine.  But with the new driver 3.016 it would only see one FF and it didn't matter which one I had on.  I reversed the driver to the previous one, used the legacy Windows Firewire drivers, and it appears to be back to stable, although I am running it all afternoon to test it.  Please keep us informed as to whether some of these issue have been corrected or at least keep your Driver Readme files up to date so that we can see what has been corrected in each release so we know when to change! Even the readme file that comes with 3.016 is really for 2.9992. ????
I guess that may all be because it is only a release candidate but it would be still nice to know when these issues get corrected in each release.

Are you using separate Firewire 800 connections for both units?  I have tried multiple units with two on Firewire 800 and one on Firewire 400 because that is the way a lot of the cards come but it doesn't always work right.  Even when I have the units on separate busses so there is lots of bandwidth.  Once you go past a single unit I have found you have to use Firewire 800 or they go out of sync.  Just a thought.

I've connected unit 2 to unit 1 by FW400 cable. Unit 1 goes to PC by FW800 cable. Thus FF800 units are daisy-chained to one 1394b port.
Some of my problems may be bandwidth related but I can't disable any I/O because all of them are in active use.

Hey Panu
I think that is your problem.  If using more than one you HAVE to use firewire 800 for all units.(in my experience and insisted on by RME) or else you run the risk of the sync problem you describe.  It is not just a bandwidth problem, it is something else(not sure what but the owners manual is pretty clear that they want you to use firewire 800 with more than one unit). I had the same problem with loads of bandwidth available and still got it.  Only corrected when I ran separate FW800 cables - and was even able to consistently make it go in and out of sync simply by changing one of the units between 800 and 400. You could try connecting the second one to the first via the second FW 800 connection but I can't vouch that that will work either.  You pretty much should be running two separate firewire 800 cables back to your computer for it to work properly.  That is what I believe RME recommends and is the only way it has worked properly for me.

Hi again,

I was on holiday but now I'm back in studio again... Thanks for your valuable hints!

FW400 cable between FF800 units worked for years in my 32-bit XP system. However, now I tried to replace it with FW800 cable. Playback works right for half a minute but after that there will occasional glitches and Errors count in Fireface begins to increase.

I tried to connect both units separately to PC. This works worst - playback gets into problems in few seconds.

I already tried to replace one FW800 cable but there was no change. I'll go to buy completely new cables next and find a new 1394b card.

I tried to reduce 2nd unit's bandwidth; no change.
I tried to give Sonar more priority; no change.

-Panu