Call of Duty 2 Patch Information now offers downloads of a Call of Duty 2 Intel Dual-Core Hyper-Thread Optimization Patch. Here's word on the 5.52 MB update:

This Call of Duty® 2 update is recommended for Windows 2000/XP users with Intel Hyper-Threading Technology (HT Technology) enabled processors, multiple processors, or systems with a dual core processor. This update will bring any supported version of Call of Duty 2 up to version 1.01. This upgrade will not affect pure server, and will not affect your ability to join or host multiplayer games with version 1.0 players. Infinity Ward worked closely with Intel to improve Call of Duty 2 performance on systems with HT Technology, multiple processors, or dual core processors. If you do not know whether you have a multi-processor, dual core, or HT Technology enabled system, please see the ReadMe file for simple instructions on checking your system.

Please note that Call of Duty 2 is a very graphically intense game. The greatest performance increase from this upgrade will be realized by selecting Optimal System Settings in the Options menu.

This update supports US/UK English, French, German, Spanish, Italian, Polish, and Russian language versions of Call of Duty 2 only.