Game Problem: Lag with Sound Blaster EAX enabled

http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_adp.php?p_faqid=76

To verify that the problem is with EAX on your sound card, try playing without EAX enabled and see if you have the same problems. Remember that EAX has an OS setting as well as a setting in the game sound settings, so disable both and see if the delay happens, then enable one or the other and see if the lag happens.

If EAX doesn't seem to be the problem, it could still be with your sound card or drivers. Sound Blaster Live cards are not the fastest, and they are sensitive to the PCI slot they are plugged into (closer to the graphics card is usually better). You should also check for the latest Sound Blaster drivers, just to make sure that's not the source of the problem.

Aside from the sound card, some systems end up sharing interrupts, which can cause odd delays. You can check in your Control Panel > System > Hardware > Device Manager, and then select "View" and "Resources by type." Look at IRQ and see what devices are sharing IRQ with your sound card. You can also see a more detailed report by running the MSInfo32 report tool (Start > Run > msinfo32 <enter>), then look at Hardware Resources > Conflicts/Sharing.

In the end, it may be that you have no problems at all—just your sound card and system can't handle the load of EAX and playing the game at the same time.