I suppose they are the same. My thought was in regard to speeding, but I think at some point over the legal limit it can result in a charge of reckless endangerment.
I typed up a post detailing Idaho's 80 mph "absolute" limit, only to go looking for the actual code to get a reference and come back empty handed.
With 80 mph speed limits on all Interstates now, it seems that the 80 mph max (and automatic reckless driving threshold) has been repealed.
As late as 2015, at least, 1 mph over the 80 mph speed limit was a felony.
...But seems to be no longer. Now it's just the general 'reasonable and prudent' crap that all states have, in order for 'recklessness' to be open to interpretation.
But, my time spent searching through the state code did provide an interesting tidbit that is contrary to what all drivers are taught, and what licensing tests cover:
You're allowed to exceed the speed limit by up to 15 miles per hour in order to safely pass a vehicle traveling slower than the posted speed limit on two-lane highways/roads with speed limits of at least 55 mph.
49-654 (2) (b):
Subject to all other applicable motor vehicles laws, a driver of a passenger car, motorcycle or pickup truck, not towing any other vehicle, may exceed the posted speed limit by up to fifteen (15) miles per hour while passing another vehicle traveling at less than the posted speed limit, in order to safely pass the vehicle. The overtaking vehicle shall return to the right-hand lane and reduce speed to the posted speed limit as soon as practicable. This paragraph shall be applicable only to passing on the left upon roadways divided into two (2) lanes providing only one (1) lane of traffic in each direction and where the posted speed limit is fifty-five (55) miles per hour or greater.
So, on two-lane highways/roads with 70 mph speed limits, it is possible to legally travel at up to 85 mph during a passing maneuver...
(Such highway/speed combinations are rare, though.)