6 Megabit down is good for an up to 40 Megabit connection? No it's not.
I think you will probably find there is a confusion between bits and bytes.
6 megabits for a 40 megabit connection is about 75k per second. Okay not good but you hardly ever see anyone say 6 megabits more likely 75k per second. Or maybe its just me brought up in the dial up modem age.
If they mean 6 megabytes per second download then it is good as 40 megabit connection divide by 8 equates to 5 megabyte per second.
Hence why I said "Perhaps if you could tell us your connection speed might help."
needs further clarification.