FPS Lag in and after entering the inventory

[Hypernetic]

Hello. I am having a few issues in single-player attack of the b team. Every time I enter my inventory page in single-player, i drop 10-15 frames. That may seem like a minor problem, except that I average at 20 fps . This lag persists about 1-3 minutes after I interact or even open up my inventory. Is there a fix for this problem? I believe it's the mod-pack because in multi-player I have no problem, but only in single-player does this occur. It is really getting annoying, so any help would be appreciated. BTW, I believe I have allocated 2 gigs of RAM and I am currently up to date with the latest 64x version of java.

[Kalbintion]

The lag is due to NEI, disable NEI and your fps wont drop from looking in inventory.

[Hypernetic]

No luck, Still lags after i enter.

[Kalbintion]

Post on the tracker then, link in signature below. Make sure to include a launcher log, in-game F3 screenshot, as well as additional information such as your computers hardware (CPU, motherboard, video, etc), whether or not you've added, removed, or otherwise modified (via configs, or other means) any mods.