UT2003 UnrealEd lag?

[GreatEmerald]

I'm experiencing horrible UnrealEd 3.0 lag (UT2003 build). Whatever I try to do (except for flying around), like selecting actors or surfaces, or rebuilding, it starts lagging like crazy. Is this issue known? I'm using a dual core Intel Core 2 Duo, graphics card ATI Radeon 2600XT, 2GB RAM. UEd statistics show: when no map is opened, it eats 85.000K memory, and if one is open, it eats 200.000K memory. Tried disabling one CPU, nothing. Sometimes it works faster, but rarely.