About 2 years ago someone told me the Intel 1G network card were extremely efficient. At that time I didn`t make much of it.
But last week I need 1Gig network for a QNX6 project. Go myself 1 Intel Pro 1Gig card for 49$ ( CDN). This card is support by QNX4, at 1G.
With QNX4 the difference in CPU usage is INCREDIBLE. With a 100Mbit card when getting a file from a QNX box through FTP, the transfer rate was close to wire speed and CPU usage close to 100%. With the 1Gig card, FTP was transferring at 22Mbytes/seconds ( limited by HD speed) but CPU usage was only 30%. Twice the bandwith and 3 times less CPU, amazing. Note that at that speed more CPU was spend in the filesystem… You don`t need to run at 1Gig to get this, you can use that card with a 100Mbits network and still get the benefit of reduced CPU usage.
This has been confirm with home made programs and not just FTP. I also made sure CPU time spend in the interrupt was taken into account in my measurement.
Needless to say I
ve switch to 1Gig everywhere ;-) I also got a 8 port 1G switch for 90$... I dont really care for the increase bandwidth, but the reduce CPU usage is what I care about.