got online with 3 different speedcheckers
What speed checkers tell you should be taken wiht a large pinch of salt. They become increasingly more unreliable the higher up you go the speed scale (I've tested most of them on a machine with a 100Mb top-notch internet connection and the majority display erratic, inconsistent behaviour and display results far from the truth).
Therefore they are not particularly accurate at the best of times.
Question, even at my lowish speeds would this help throughput as it's 10/100/1000 compared to the present 7 yr old 10/100 type??
Are you serious ? You've hardly got anywhere near a 100Mb internet connection and yet you're looking at a gigabit switch ? I bet you don't even push enough packets round your local network to hit the buffers on a 100Mb switch.
Save your money for something else. Or if you want to spend money on a switch, go buy a decent
managed 10/100 model. That will give you some extra knobs to tweak should you feel the need.