At the vSphere 5.1 release time frame, the 16Gb Fibre Channel fabric and 16Gb FC cards have become generally available. The release of the 16Gb FC driver on the VSphere platform can now take full advantage of the new 16Gb FC HBA and thus have better storage I/O performance.
As described in the paper “Storage I/O Performance on vSphere 5.1 over 16Gb Fibre Channel”, the storage I/O throughput has doubled for the larger block I/Os compared to the 8Gb FC. In the paper it uses single storage I/O worker to show the throughput has improved with better CPU efficiency per I/O. For random I/Os in small block sizes, 16Gb FC can attain much higher I/Os per second than a 8Gb FC connection.