I'm considering to buy a MAGMA P7R4 7-Slot PCI Expansion Chassis to run three multiface units. Therefor I'm trying to calculate the overall transfer rate needed for all three cards while using all inputs and all outputs at the same time(!). I'm running the cards with a sampling rate of 48khz.

one card has 18 inputs => three cards have 54 inputs
one card has 18 outputs => three cards have 54 outputs

three cards have all in all 108 IOs

one sample is transfered as a double word of 32 Bit => 4 byte
one channel has a transfer rate of 48khz x 4 Byte = 192KB/sec
108 IOs have a transfer rate of 108 x 192 KB/sec = 20'736 KB/sec = 20.74 MB/sec

If this calculation is correct then a transfer rate of 132 MB/sec would be more then enough to run these three cards without dropouts. 132 MB/sec is the transfer rate between PCI Expansion Chassis and the PC.

Is this correct or am i missing something?

Any help is much appreciated
Thanx
steff