Question: can 10gb sfp run at 1gb?
Answer: In fact, most SFP and SFP+ transceivers only run at its rated speed and the transceivers at both end of the cable should at the same speed. ... When sticking a 1Gb SFP module in the 10G SFP+ port, the 10Gb switch will only run at 1Gb. As thus you can link it to gigabit switch.