Hi.

I just recently built a new machine which I'v now done every secound year for the last 12 years. The new ones a 7i 920 cpu, 12 GB ram, 750 watts coisar power, ATI radeon sapphire PCI expresscard and win7 64bit.
I built the machine home and I used a M-audio 1814 firewire card in the included  VIA firewire slot.

I was amazed by the power and stability. I managed:

80 tracks
480 plugins ( waves ssl EQ and Sonnox comp)
64 buffersize
80 percent stabel cpu meter in Nuendo 4 with no glitching or crackling what so ever.

I took the machine to my studio where I installed FF800 with the newest driver and used the same Firewire slot.

On some projects I'm not able to even play 40 tracks without any plugs in 64 buffersize on other songs I manage to run 10 - 20 plugs in 128 buffersize but the CPU meter jumps iradically up and down from 30 to 100 percent and I get the so much hated crackles.  On other songs it opens at 100 percent, but as soon as I hit play it falls down to 30 percent but takes jumps up to 60.

This gets me thinking. The only thing that is different is the soundcard. I have always been a strong believer in RME and it's drivers, but now I get confused. I teach about 60 students each week and they are coming to my studio and I need to get this thing running like Forrest Gump as soon as possible after Christmas Holidays.
I also have 3 records to do in the next 2 months...

I have the latest drivers for everything.
I have tried with a different Iee card. (NEC)
I have taken out the UAD-1's and the POC.
There are no IDE disks in my machine.
Everything is installed clean.

Shall I try a firewire 800 Texas Instrument PCI card? If so, what?

Please, help me put here.

Best regards

Bluemusic