To reduce ping and lag, type those into your console and remove this § mark, and then start to type.
Connection Settings: Cable/DSL - 256k and faster
/rate 25000
/snaps 20
/cl_maxpackets 60
Connection Settings: Cable/DSL & Dual ISDN - 128k
/rate 15000
/snaps 20
/cl_maxpackets 60
Connection Settings: Single ISDN - 64k
/rate 7000
/snaps 20
/cl_maxpackets 30
Connection Settings: 56k Modem
/rate 4000
/snaps 20
/cl_maxpackets 15
Connection
/rate "25000"
/cl_maxpackets "80"
/cl_timenudge "0"
/cl_packetdup "0"
/snaps "20"
Commands to use in a group to lower you're ping by 40
/cl_maxpackets 100
/cl_timenudge -50
/pb_sleep 500
/rate 33000
/snaps 20
Note:However, if you use voice comms software (like TeamSpeak or Ventrillo) when playing with clan-mates or whatever then you might then want to make rate lower to leave enough room for the bandwidth the voice comms software uses. In that case, a 256kps download speed connection might be better with, say, rate 15000; while a 512kps or faster connection could probably stick with rate 25000. The amount to deduct would depend on the amount of bandwidth required by whatever codec you are using with your chosen voice comms software.