I am testing our real-time application on a P35 + ICH9 motherboard.  QNX boots fine.  A newer devb-eide I was given runs
 the ICH9 in DMA as well.  Everything looks great, but when I run my real-time application I see a very long interrupt 
latency occuring about every 2 seconds on the a/d converter interrupt.  I have made sure I have a clean IRQ with nothing
 else sharing (tested both IRQ 3 and 4).  This is a Gigabyte GA-P35-S3G.

The same test with the same conditions and hardware (just swapping the motherboards) works fine on a Gigabyte GA-945PL-
S3E which uses the 945 chipset + ICH7.  Both tests are using an E4500 Core 2 Duo and the non-SMP kernel.

Since it is very repeatable with this 2 second interval it seems like some kind of timer.  Any help appreciated.