Terrible MIDI latency problems

[grantmaloysmith]

I am new to Protools and the RACK 003 (on a Mac Pro), after 20 years using Cakewalk/Sonar on the PC. I have nothing but MIDI problems now. On Sonar there was no latency, now it is unplayable on the $10,000 Protools setup that I have invested in. I have simplified my setup so that one keyboard is simply a controller, connected to the MIDI in on the RACK003. Then I have two computers; each with a sound card and MIDI input ... one runs Miroslav Philharmonik, and the other PC runs a Kontact player. These computers are directly connected to MIDI out 1 and MIDI out 2 respectively on the RACK 003.

Even if I am not recording, and I set up a simple channel routed to MIDI out 1, channel 1, it plays on computer 1, of course, but with a HUGE latency. It is actually unusable. The only way I can seem to counteract it is to set the hardware playback buffer to be very small, like 32 or 64. But then when I am working on a big track with lots of audio channels, this small buffer is not enough to handle it.

At first glance I would say that the MIDI implementation in Protools is very weak. But at the same time, I am sure that there are many little things that I am simply not aware of how to do, which might be able to improve this.

By the way, if I directly connect the keyboard midi out to either computer's MIDI in, there is zero latency, so it is not the keyboard or the computers. Somehow the problem lies in either the RACK 003, or Protools, or some combinatio.

If anyone else has gone through this and has any advice for me, I would be really grateful.

I am running Protools 7.4.2 on a Mac Pro 8-core machine with leopard 10.5.3.
The RACK003 is connected via firewire, of course. The keyboard is connected via regular MIDI to the RACK003 MIDI in. The 2 outboard computers (sample playback engines) are connected directly to MIDI outputs 2 and 3 on the RACK003. There is no other hardware in the loop.

Thanks,
Grant