Possible hardware problem, high latency with cpu load

[lagreca]

I first thought this was a traffic shaping problem:  http://forum.pfsense.org/index.php/topic,13779.0.html

But now I believe it might be a hardware problem.  I have tried pfSense on both:
Dell OptiPlex GX1
Dell Dimension 2400

both with 3com 905b and 3c905c NIC's.

The symptoms are high latency when pinging the internal IP of the firewall when any load is put on the firewall.  Example would be pinging 192.168.3.1 (internal interface/LAN) and trying to load traffic shaper rules in webui.  While the webui is loading the rules the latency jumps to 400ms, then when the webui is done loading, the ping times go back to normal, around 0-3ms.

Also when I do a speedtest.net test, the download portion of the test, VOIP gets choppy at first, then clears up, and ping times are high (200-400ms).  When it comes time to the upload portion of the test, ping times remain normal, and VOIP sounds fine.

How can I tell if this is a driver or hardware issue?  I looked in the logs, but haven't seen anything I would recognize.

[cmb]

I don't think it's a hardware problem, latency to your LAN is the same as to anything on the Internet because of the way the 1.2 shaper queues, sounds normal.

[lagreca]

Whats interesting is that I have a T-1 (symmetrical bandwidth), and I ONLY get high latency on the download portion of the test, NOT the upload.

Here are pings to the pfSense internal interface:

Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time=31ms TTL=64  <–download test starts
Reply from 192.168.3.1: bytes=32 time=170ms TTL=64
Reply from 192.168.3.1: bytes=32 time=306ms TTL=64
Reply from 192.168.3.1: bytes=32 time=27ms TTL=64
Reply from 192.168.3.1: bytes=32 time=104ms TTL=64
Reply from 192.168.3.1: bytes=32 time=243ms TTL=64
Reply from 192.168.3.1: bytes=32 time=372ms TTL=64
Reply from 192.168.3.1: bytes=32 time=510ms TTL=64
Reply from 192.168.3.1: bytes=32 time=204ms TTL=64
Reply from 192.168.3.1: bytes=32 time=33ms TTL=64  <--download test ends
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64  <-- upload test starts
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64  <-- upload test ends
Reply from 192.168.3.1: bytes=32 time<1ms TTL=64

Ping statistics for 192.168.3.1:
    Packets: Sent = 41, Received = 41, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 510ms, Average = 48ms

VOIP is getting mangled because of this.  But I don't know what is causing it or how to get ride of it.  I do have the traffic shaper turned on and data is flowing into the VOIP queues.  But I still have the problem.