Well i got problem.

For example lets take serwer "xxx".

In dos mode ping i got: 10-15 ms to xxx serwer
In quakeworld with new ezquake on spec i got: 33 ping
so now everything is ok and normal. Byt befor update i was 33 ping on spec and 25 in game
now i got 40 in gameand 33 on spec.

I know one more player who got same bug.

How to fix it?

You on these?:

cl_physfps "77"
cl_physfps_spectator "77"

avenger: isp routings change
to check your routing to a given ip, type in windows console:
tracert ip

Try rolling back to the older client version (just rename or so for testing). Does it still happen then using the same cfg?