We've had our Model X with Tesla's "hardware 2" for about a month. The "hardware" in hardware 2 refers to the cameras, sensors, and computers in the car that allow the Autopilot software to function.

Hardware 1 consisted of one forward-facing camera made by vendor Mobile Eye, one bumper-mounted radar unit, and bunch of ultrasonic "sonar" sensors on the front and rear bumpers. Hardware 2 consists of up to eight cameras located around the vehicle, a radar unit located in the front grille of the car, and sonar sensors in the bumpers and doors.

Ironically, while hardware 2 is more advanced than hardware 1, the hardware 1 software is more mature and feature-rich than hardware 2, currently. We thought it was useful to compare the current functionality of the software as of publication, knowing that it will keep improving through Tesla's over-the-air software updates.

But let's make one thing clear:  Tesla's autopilot software on hardware 1 and 2 cars is totally awesome and more advanced than anything on the road today. Renting either our hardware 1 or hardware 2 car will be a joy for you.

Hardware 1
The Hardware 1 autopilot is on software version 8.1. This software allows the car to drive itself (with driver supervision) on highways and city streets. It does not recognize traffic lights or stop signs, but it is nearly flawless on recognizing where lanes are, on following cars in front of you, and making driving a joy.

In addition to autopilot, the hardware 1 car will self park either in perpendicular and parallel parking spaces. It has auto-sensing wipers that detect rain and the intensity of rain and respond accordingly. It has headlights that dim automatically when a car approaches, and that return to bright when the car has passed. It also nearly flawlessly detects speed limit changes using its optical camera.

On freeways, the car drives itself flawlessly. It stays between the lanes, doesn't bobble back and forth between the lines, brakes smoothly when traffic slows, and evenly speeds up when traffic accelerates. Overall it feels like mature software that reacts as you would expect it.

Hardware 2
Hardware 2 is also on software version 8.1. Compared to Hardware 1, Hardware 2 is far more advanced and one would expect that the software would be similarly advanced. Experience shows, however, that the "enhanced" Autopilot software on Hardware 2 cars has a long way to go.

While Tesla bills Hardware 2 cars as having "enhanced" Autopilot, and while we're sure that it will one day be more advanced, it currently is not. We find that the car's sensing of the lane lines is sometimes erratic, with the lines bouncing around, even when the car is stationary. We find that the cameras fail to see recognize the lines sometimes, temporarily disabling Autopilot activation. But it will see those same lines that have not changed, seconds later, allowing activation.

Additionally, it seems that the long distance forward camera and the short distance forward camera are not exchanging information well, particularly on right-sweeping corners. The short-range camera sees the lines are bending to the right or left, but the long range camera doesn't seem to see the lines. As a result, the long range camera will sense cars ahead on the corner as being directly in front of you, when they are actually in a separate lane. The result is that the car will sometimes brake unexpectedly as it thinks a car is in front and it needs to slow down. It quickly figures out the problem, but it can be disconcerting when you're not ready for it.

The car also tends to drift within the lane or "bobble" a bit. The Hardware 1 car, however, is rock solid with no bobbling.

From a feature standpoint, the Hardware 2 cars lack autodimming headlights, auto-sensing wipers, and perpendicular parking. Additionally, the speed sign detection is deficient; it misses speed signs that the Hardware 1 cars easily catch.

We don't want to be overly down on Hardware 2. It's still damned amazing, and the fit and finish of the newer Hardware 2 cars is superior to the Hardware 1 cars. Tesla continues to improve Hardware 2 software. In the month we've had the car, we've already seen software updates pushed to us that improved how Autopilot behaves. We expect that these improvements will continue and that Hardware 2 will soon surpass the capability of Hardware 1, perhaps even in a couple of months. One of our renters couldn't tell the difference between Hardware 1 and 2, so perhaps we're just being overly detrimental.

How fast is Tesla improving? They currently plan fully self-driving cars within two years.

So rent either of our cars with confidence that they will drive themselves on the highway with driver supervision. They're both amazing! But as of this writing, hardware 2 is still improving. If you want to see where it's going, check out this video: