Quote: "And it should be possible to send 60 per second as I CAN do this with multisync"
UDP is not TCP. Apart from sending signals down a wire, they are almost nothing like each other, so what will work well with one won't with the other.
TCP will throttle the transmissions. It will stop transmission totally if the remote buffer is full. It will block your program if the local buffer is full. It will retransmit missing packets, and ensure that ordering is maintained. It will coalesce multiple transmissions on your part into larger packets and transmit fewer of them.
UDP doesn't do any of that. If the remote buffer is full, the packet will be dropped. If the local buffer if full, the packet will be dropped. If a packet is missing, it won't do anything. If the packet arrives out of order, it won't do anything. Packets will be transmitted immediately, and not coalesced, so each send will create a new packet.
Because of all that extra work the TCP driver is doing for you, the transmissions are more efficient, and the blocking makes it seem as if things are smoother. The downside is that you could lose the smoothness when you actually involve a real network (ie, a piece of wire or wireless rather than just data transfers within the network driver) where packets can be lost or delayed.
Did you know that most commercial network games transmit their packets at around 10 to 15 times per second?
For movement they generally use dead-reckoning to fill in the games, with auto-correction of the data over short spans of time (eg, interpolation says you should be at one spot but the current packet says you should be at another, so adjust the position over time to correct for the difference).
For RTS's the packets are usually based on sending timestamped commands, with the timestamp set in the immediate future, so small delays have no impact (ie, these units to attack those units, queue up the command locally for a future time, and transmit the same message with the same future time to all other clients).
Using UDP isn't just about pumping data down the wire, but doing it cleverly and with a little sleight-of-hand where needed. It's about making it look right even if things become a little out of sync - because things WILL go out of sync, as you've already seen.
