Some issues...

[khaotik]

interpolate 1 forces the client to interpolate on client as well as server.
cl_smooth 1
cl_smoothtime .1 smoothes prediction->position over time specified.

Also, interpolate 1 also works well with
cl_lagcomp_error check 1

this checks Users client and server positions.

Higher latency players want error check on.
Low lat players want it off.

[BioHaZarD69]

interpolate 1 forces the client to interpolate on client as well as server.
cl_smooth 1
cl_smoothtime .1 smoothes prediction->position over time specified.

Also, interpolate 1 also works well with
cl_lagcomp_error check 1

this checks Users client and server positions.

Higher latency players want error check on.
Low lat players want it off.

Now here is a perfect example of what im saying right here!
see these setting seem to work for Khaotik..BUT if i were to use cl_smooth "1" and cl_smoothtime settings my game would run shitty,so you see its all in the rig you have and the settings you are running your vid card at..
my rig simply is Intel core2 duo with Nvidia GTX 275 6 gigs of corsair ddr2 800 mhz...OCed at processor running at 3.61 ghz from the 3.0 stock and memory is OCed to 2.20 dram voltage and timings at 5-5-5-12 from the stock 1.9 voltage and the 5-5-5-18 timings... as i said its a matter of trying different things with different rigs...one setting might work great for you and may not work so great for me....test stuff out and always make backups of your files before editting and remember what you change so you can change it back if it isnt working for ya.