Given the size of a TCP packet is 60 bytes, there is a SYN Flood attack on a computer made by a 100 Mb bandwidth, the question is how many syn packets are sent in a second? Is there any formula for calculating?
Attack using 100 Mbps link means you have to create roughly 210k packets to fully utilize your 100 Mbps connection.
100 Mbps = 12500000 Bytes
12500000 / 60 Bytes = 208333.3333333333 Packets
Depending on your machine you will require multiple processes to generate this amount of packets, single process won't generate these many packets in one second.