Performance Issues? Viva Viagra! lol j.k
Please post a CoH_Helper and HiJack This! report and we might see a possible cause.
Also, I recommend also putting said information into a new thread in the "Techical Issues & Bugs" forum here-- they have a lot of big brains over there that have seen nearly everything and can probably offer very specific advice.
In any case, best of luck with your issue and welcome back to CoX! 
Leader of Legion of Valor/Fallen Legion (Victory server)
http://legionofvalor.guildportal.com / http://fallenlegion.guildportal.com
StainedGlassScarlet - L50 Spines/Inv Scrapper | Badges: 1,396
Avatar detail taken from full-size piece by Douglas Shuler here
Edit: Sorry, just saw the message about the correct place to post. Posting there now.
Hello all. Thank you for your time. I'm an older player that has come back recently. Since the last time I played, I've gotten a new computer. A far better one that the last.
Here's the problem. Every time I am in a group, I get the most horrendous lag when we hit up a mob. It isn't your normal, every day MMO lag. It's serious 1 frame every 10 seconds kind of lag. This has puzzled me because I know for sure my computer can run this silly little game. So, here's what I'm working with.
XP SP3, 1.8 dual core, 2 gig of ram, NVidea 8500 or 8600 or something. Fiber optic internet. All the video drivers are up to date. Use the unload/reloadgfx commands in game and they don't help. No extra programs running in the background. No viruses according to Kaspersky Anti Virus. No spyware according to Spyware Doctor. That's all I can think of at the moment. I hope I provided enough information.
If anyone has any ideas on why I might be performing so badly, I would really love that. Thank you for your time.