Can I have 2Gbit over 1Gbit Nics [closed]

Duplex is a bit of a misnomer in Gigabit Ethernet as there are not separate send and receive channels like in 10Mb or 100Mb Ethernet. In the lower speeds 2 wires are used to send, and 2 to receive. The other 4 wires aren't used at all (for data anyway).

In Gigabit Ethernet all 4 pairs are used to send and receive. It uses a 2 of 5 trellis coding: For simplicity sake we'll say that each end uses 2 of 5 possible "voltages", one for "1" and the other for "0". It measures the "voltage" on the line, subtracts the "voltage" of what the near side is transmitting and thereby knows what the far end is sending.

The actual details of how this works are more complicated, but the end effect is the same. Regardless Gigabit Ethernet can transfer 2Gbps of aggregate data under ideal circumstances. "Real World" tests will frequently be slower. Also, the Ethernet frames suck down about ~10% overhead, TCP and IP suck down another ~10%; so TCP based tests will usually max out in the mid-80% range.

Your switch must have more than just 24 ports as the switching capacity is more than 48Gb (the 24 ports x 2Gb). The switch fabric is the internal switching capacity and they usually limit the advertised number to the external switching capacity.