Blackviper is worth the look. He has W7 tips and a list of what to disable/ set to manual in component services, depending on how you use machine.
Skuzzy has a great Hint and Tips post as well.
Disable any auto updates, MS, virus, adobe, java,
You can try something called Advanced Shortcut Composer, its freeware, you can configure the AH desktop icon to have a higher priority with cpu.
Multi Media Class Scheduler, MMCS. Google this, theres a tweak to disable a throttleing technique, W7 uses, reguarding sound. I have had sound issues that I thought were vid issues, disable sound card in device manager and then play the game. Same issues, or do they go away?
All drivers current and up to date? sound, vid, lan.
Network Interface Card, NIC. In device manager, advanced tab. Auto negotation/ full duplex. Is your ISP service delivering full service?
Disable CPU core parking.
Does issue happen in offline mode?
Wireless routers have some type of issue, something about constantly searching or looking for signal???????????