cl_predict tries to predict the movement of the players.
About cl_maxpackets I will copy a text inside aprq2's readme:
aprq2_readme.txt wrote:---------------------------
About cl_maxpackets (from q2pro)
---------------------------
VQ2 sends client movement packets to the server each client frame.
If your framerate is high (more than 100 fps), and your network bandwidth is low (modem),
this results in bandwidth overrun and, therefore, consistent lag. That's why every modem user
had to to degrade performance of their machine by clamping framerate with cl_maxfps cvar.
cl_maxpackets specifies maximum number of packets
sent to the server each second, so you don't longer need to clamp framerate.
This uses a small hack from Fuzzquake2 mod, where packets are generated each frame,
but some of them are dropped.
Normally, this will result in prediction errors, but if there are less than 3 packets dropped,
everything works fine, thanks to q2 engine architecture.
Okay, heres the point. mine and my mates maxpackets was both at 0, when he changed it to one third of his maxfps, the net_graph started to grove big alps , so maxpackets 0 is better, tryed the "ATI-BUG-FIXES", didnt help much, only more fps. So, its not that,