QUESTION Sangoma A200 dahdi timing?

[CoinTos]

I am having trouble wrapping my head around how a sangoma card works with dahdi. I can't get the timing to be what I believe is what it should be (nothing below 99.975). When I originally got this card I put in my 1u intel sr1500alsas, timing just plain sucked no matter what I did. I believe the reason is that it shared irq with my sas backplate controller even with APIC assignment.

I then picked up a hp dc7800 workstation. I like these workstation because you can disable irq for onboard things like sound and such plus they are small form factor and make great a htpc with a couple of hardware addons. The dc7800 does better in that the card is on it's own IRQ but it dahdi_test results tend to do a hi, low, lower , repeat %.

Opened pseudo dahdi interface, measuring accuracy...
99.964% 99.994% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998%
99.967% 99.962% 99.998% 99.967% 99.963% 99.998% 99.967% 99.963%
99.998% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998% 99.967%
99.963% 99.998% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998%
99.967% 99.963% 99.998% 99.967% 99.963% 99.998% 99.966% 99.963%
99.998% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998% 99.967%
99.963% 99.998% 99.967% 99.963% 99.999% 99.967% 99.963% 99.998%
99.968% 99.963% 99.998% 99.967% 99.964% 99.998% 99.967% 99.963%
99.997% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998% 99.967%
99.963% 99.998% 99.967% 99.963% 99.998% 99.967% 99.963% 99.998% ^C
--- Results after 80 passes ---
Best: 99.999% -- Worst: 99.962% -- Average: 99.976105%
Cummulative Accuracy (not per pass): 99.998

On the above my average is always just above 99.975%.
I do get runs that go perfectly like this:

Opened pseudo dahdi interface, measuring accuracy...
99.998% 99.995% 99.998% 99.998% 99.998% 99.998% 99.998% 99.998%
99.998% 99.997% 99.997% 99.997% 99.998% 99.997% 99.998% 99.998%
99.998% 99.998% 99.998% 99.998% 99.998% 99.998% 99.999% 99.998%
99.998% 99.998% 99.998% 99.998% 99.998% 99.998% 99.998% 99.998% ^C
--- Results after 32 passes ---
Best: 99.999% -- Worst: 99.995% -- Average: 99.997706%
Cummulative Accuracy (not per pass): 99.998

What I just don't get it, what is the magic system that will give the second results all the time? Are these result bad because if you read sangoma support wiki anything above 99.9% is good to them. I have tried researching it off and on for the last weekand a bit with work getting in the way so I figure before I make the dc7800 my active pbx machine and turn the 1u into a esxi box I get any opinions, suggestions or solutions anyone has found to work/help.

Thank in advance.

HP DC7800:
│ PIAF Installed Version = 2.0.6.4 under *HARDWARE*
│ FreePBX Version = 2.11.0.8
│ Running Asterisk Version = 11.4.0
│ Asterisk Source Version = 11.4.0
│ Dahdi Source Version = 2.6.2
│ Libpri Source Version = 1.4.12
│ IP Address = 192.168.1.57 on eth0
│ Operating System = CentOS release 6.4 (Final)
│ Kernel Version = 2.6.32-358.6.2.el6.x86_64 - 64 Bit
Sangoma A20200DE - 4fxs W/EC.