srcds lag problem

[city wok]

ok i finally got my server working today, but now i have a serious lag problem doesnt lag unless theres 6+ people in the server then my fps when im playing drops making it almost unplayable, im using casys source config in my autoexec.cfg, also noticed when alot of ppl in server most peoples ping is 100+ anyone know why this is and any ideas on how to raise my fps ><? also i have srcdsfpsboost.exe running and i put in command line -heapsize 524288 -tickrate 33
heres my PC specs:
mobile AMD Athlon™ XP-M 1600+, MMX, 3DNow, ~1.4GHz
1 gig DDR ram
radeon 9550 (driver = omega 3.8.330)

addons are:
mani/deathmatch/sourceMM

i have these in server.cfg
sv_maxrate 20000
sv_maxupdaterate 60
sv_minupdaterate 33
sv_maxunlag 10


edit: also forgot to add im on DSL with connection speed of 3.2mbps