99.9% of game pauses are due to resource issues with the computer. Whenever a computer runs out of resources, the game will be paused as the CPU and operating system try to figure out a way to keep everything running.
The game will give you a clue about this. Open the "Net Status" panel (right-click on the clipboard map in the tower while Online) and note the "Variance" graph. It should be flat lined in the middle. I bet it is spiking on you, which is an indication the CPU is off doing other things.
DXDIAG only marginally helps get to the resource issue. The real work starts in the Windows Task Manager. A normal Windows XP system has around 19 to 21 processes running in the background. Open the Teask Manger, select the "Processes" tab, then look in the lower left hand corner for the total count.
Then look to the immediate right of that number to see the CPU usage. With nothing running on the desktop, it sould bouncing like a heartbeat from 0 to 1 (occasionally 2) percent. No higher. Watch it for a minute or two.
Resource issues also happen with sound cards as well. Dumb sound devices like AC97 sound devices require an enormous amout of CPU cycles compared to almost any PCI sound card. Turn down the hardware acceleration on those dumb devices as all that slider is doing is adjusting the priority of the sounds played by the CPU.
Lastly, pay attention to the sticky posts in this forum. They contain virtually everything I have stated here, in greater detail.
It is your computer to control. The game cannot fix resource issues.