Do I really need a firewire card?

im very supprised that your runnin OK with a via chipset, but hay

a good TI firewire card pci is 20.00 the card you showd me is fine
but overpriced.

im sure Focusrite tells yout to use a TI chipset too !! but hay ..

Check the chipset and type of FireWire card. We recommend FireWire 400-only, non-combo (i.e. not with USB AND FireWire ports) cards with either a Texas Instruments or a VIA chipset, from a known brand manufacturer such as Belkin, Lacie or SIIG.
Other chipsets and models also work, but the above specs will give the best results. For more information see FireWire compatibility article.

bob: what motherboard are you running >?

What draws attention to the firewire port being suspect to problems are problems of the type you were having when you were using the new driver for your audio interface. Things like the lagginess you experienced when arming a track, audio drop outs, and pops and clicks when playing back projects or recording.

You have a pretty decent system. What is your ASIO performance like, now?

If you can, for instance, run the Artist demos (ShiftyAndTheBigShots_LanceJones and Unified Tribe's Guilty) that come with X1 and SONAR 8, at a 64 samples buffer size (with little or no pops, clicks, or glitches,) you're doing pretty OK.

What is the speed of your RAM? You may see some performance improvement, if your RAM is just 800 MHz speed and you upgrade to 1600 MHz speed.

And/Or if you upgrade your CPU to a i7 970 or something higher, but if you're running projects with a good number of effects and tracks already at a 64 samples setting, you're already pretty good to go. If it aint broke don't fix it.

But since you have installed an older driver for your audio interface and you don't have that latency you used to experience with the newer driver, it appears your experience is probably near optimal, already.

Nonetheless, if you have the money to spare and you really value attempting to get your system running as good as you can, there is nothing wrong with getting a TI chipset firewire card to see if you get any improvement through it's use. That choice is yours. :) So if you get the TI card and don't see any improvement, don't blame us. :) Not all non-TI chipets are problematic. 

Something you can do for a bit better recording experience and for tighter audio and MIDI sync in your projects is to manually adjust for record latency, if you want to. Here's a post that will help you to do that: http://forum.cakewalk.com/fb.ashx?m=1302373

Link looks interesting Thomas - thanks!

Those running on TI - do you run legacy 64 bit driver? My mindset is right now that the only reasoning to do this is that the Windows 64 bit 1394 Legacy driver may have more latency than a TI driver. However I cannot see how a TI chipset could be faster than a internal VIA in built chipset. Am I wrong?

 
The issue isn't that TI is "faster"... but rather that most Firewire units won't have a compatibility issue with it.
 
If your DAW can currently run substantial loads (glitch-free) at the smallest ASIO buffer sizes, moving to a TI unit will most likely not yield additional performance.
If you're running a well-configured i7 based DAW... and you can't do this... I'd replace the Firewire controller with a quality TI chipset unit.
 
Regarding "legacy" mode for the Firewire controller's driver:
That depends solely on the audio interface's driver.
Audio Interfaces that haven't had a recent driver update will most likely need to run in legacy mode (ie: Tascam FW1884).  Those that have had a recent driver update will likely have to be run in default mode (ie: Steinberg MR816).

NB Thomas hardware and software config is all optimal,

 
Forgive my ignorance, but what does "NB" mean?

alex: get  a proper TI card then you will know and pci is the way to go !!

when I got my MOTU I first tried the onboard firewire, which was VIA.  it had pops and clicks during playback.  they weren't bad, not constant, but annoying for sure.  I first bought a PCIe 1394A/B combo card and that was a mistake, it made things worse.
then I bought a PCIe 1394A only card by SIIG based on advice I got in the forum.  unfortunately, all SIIG cards are NOT TI chipset and they put a sticker over the top of the chip so it's not easy to tell from looking at the picture.
that card was also a problem.
I finally bought a TI chipset (can't remember the manufacturer right now) 1394A card and things went smoothly!

I couldn't be happier with it!

Uh oh, the card in the link above is no longer available at Guitar Center.

Here's one that appears to still be available and that works, though it's not made by ADS: http://www.newegg.com/Product/Product.aspx?Item=N82E16815103103

Built my friend a decent computer a couple years ago using an MSI I7 motherboard with onboard Firewire port. Nothing but glitches, dropouts and gui problems with a Fireface 800. Also, the oboard Firewire port would not let me monitor video playback from Adobe Premier. Added a PCI Firewire card with TI chipset completely solved the problem. Not sure if the onboard Firewire port had sharing conlicts or if it used a chipset that was not IEEE compliant which is usually the problem. If you are not having problems like that then I wouldn't worry about it.

  As luck has it, my ASUS board came with the VIA 6308 chipset recommended by Focusrite, and so far I've not had as much as a hiccup from it with the ASIO buffer set to the lowest setting, with a latency of 5.4 ms. One minute of stereo audio recorded at 24/96 generates 33mb of data, which means each second a track is recording it generates .55mb of data; theoretically, if you were recording 100 stereo tracks simultaneously, the task should only require 55mbs of throughput for a firewire chipset to handle the load. A firewire card that can handle 100mbs of data flow should keep up with no problems. You're more likely to encounter a bottleneck with SATA drives than with a firewire chipset that is functioning properly.