HW3 vs. HW4 FSD Comparison - Do I Need AI4 to Use FSD?

Added: 2026-05-12

[00:00:00]A lot of people are always curious how full self-driving behaves on hardware 4 versus hardware 3. Does hardware 3 check all the boxes for daily driving? We're going to find out. I'm going to test both of these on the exact same route.

[00:00:14]We're going to do a comparison side by side.

[00:00:34]The first test here is with hardware 3.

[00:00:37]This is the latest version of 2026.14.3 which is also known as 12.6.4.

[00:00:44]I'm leaving this neighborhood area and I'm taking my car on city streets and also on the highway. I'm going to do the exact same route again as I mentioned earlier with hardware 4. We're going to see if there are any noticeable differences, if the cars behave differently. I'm very curious to find out if hardware 3 is performing very similarly to hardware 4. In my opinion, every single time I drive with hardware 3, it drives so smoothly. I really don't have any issues with it. Now, coming around this corner here, it is a 35 mph zone. And you're going to see here a speed limit sign showing up on the right side. It's set to 35 mph max. There was the sign. And then right after the sign, you're going to see the speed actually starts to go up. I'm talking about the speed of my car. It's starting to go faster, a little bit more than I am comfortable with. Thankfully, with hardware 3, you can adjust the max speed as shown here by using the right scroll wheel on the steering wheel and then you move it downward and that changes the speed that you're traveling and you can fine-tune adjust that at any time on city streets or highways. It's really nice and I would consider this an advantage over using hardware 4. Now, one thing I've noticed on hardware 3 is that on city streets, you cannot change the speed profile. There are three speed profiles with hardware 3. There is chill, standard, and hurry. With hardware 4, there are five speed profiles, and you can change them on city streets. So, that's nice with hardware 4, but again, you're missing that fine-tune adjustment capability.

[00:02:39]Now, as we get onto the highway here, let's just talk about some of the differences that I've observed between Hardware 3 and Hardware 4. Hardware 3 on 1264 handles highway driving really, really well for the vast majority of owners. It has very smooth lane changes.

[00:03:00]It offers end toend navigation. It will maintain the speed reasonably well. Just like hardware 4 though, it will sometimes hit potholes and it is not perfect and that's why these are supervised systems, but for the most part, these operate so well that they're very practical for daily use. I would say some of the key differences for highway driving between hardware 3 and hardware 4 would be a little bit quicker response times with hardware 4, perhaps a little bit smoother, but generally they're very similar.

[00:03:40]You'll see the car is naturally going 81 miles per hour. Now, this is 11 miles over the speed limit. In some parts of the world, this is unheard of. Like, you would never go this fast, but I will say this is very natural. So, in this area, most people drive faster. I would say uh I would say 8 or 9 miles over the speed limit is very typical. Uh and it's not uncommon to go 10 miles over or a little bit more over than that. And the nice thing is that you can dial it back down again. You can use the scroll wheel on the highways just as you can on the city streets. And you can also adjust the speed profile when you're on the highway. And here I'm getting off of the highway just as I had planned. And then I'm deleting a waypoint to head back to where I started.

[00:04:34]And here you can see it's getting right back onto the highway and heading back to where I came from. Now getting onto the highway here is very smooth. No issues. Look how it hugs the corner there. It accelerates now. It's at 30.

[00:04:51]It's going up now to 35.

[00:04:56]It's taking a very legitimate, safe, and standard speed going on this ramp. And then as soon as it finishes the ramp, you're going to see here 35. It's going to ramp all the way up. Now, let's see if it goes 81 the same as it did before.

[00:05:13]Here it's speeding up and it's merging, getting over very naturally there.

[00:05:22]Going 71 now. Trying to get over again another lane. Now, this is the fastest lane. And here we are at 80, 81, 82, 83.

[00:05:32]Wow. So, 85 is the maximum speed that full self-driving will go. It doesn't matter what hardware platform you're using. And here you can see it maxes out at 85 there.

[00:05:52]Now, it's in the far right lane and we're coming up to that major interchange here again. And there's a lot of cars that merge onto the highway.

[00:06:00]You can see the maps in the upper right there. This is the main highway uh coming up. And after we go over this bridge, you're going to see there's a lot of cars merging and I'm getting off at the exit basically right after that.

[00:06:19]So, watch what happens. I'm in the far right lane and there's all these cars.

[00:06:24]You can see them on the right coming.

[00:06:26]Watch what my car does.

[00:06:39]It moves over into the gap here at the perfect time. In previous versions, it wouldn't get over as soon. This felt very natural. It filled the gap. It's going an appropriate speed. The exit's coming up. There's plenty of time. I don't feel stressed. In previous versions, like I said, sometimes it just wouldn't get over soon enough, and you'd be wondering when when.

[00:07:09]So, here now we're getting off. And you're going to see the road that we take here is right after we pass over the highway. And it's basically the first left lane after the highway. And sometimes it doesn't matter whether it's hardware 4 or hardware 3. Sometimes it will actually stay all see this left turn lane. That's to get onto the highway. And it hardware 3 actually gets into the left turn lane and then immediately realizes, oh, I need to get over one more lane. Sometimes it will stay in that lane and make a mistake.

[00:07:46]But this time, I was very happy to see it got out of that lane fairly quickly.

[00:07:51]Now, Hardware 3 owners have been stuck on the same version of FSD since early 2025.

[00:07:59]However, a lot of owners have been speculating and raving in some cases about how it's gotten better over time.

[00:08:07]Everything has been very subtle, though.

[00:08:10]It's very, very minor. So, even though it is the same build, Tesla is deploying small refinements over time. This was especially noticeable when 2026.8.6 six came out where it started getting over earlier than it used to and it seemed to be kind of pingponging within lanes. There were noticeable things that stood out that a lot of owners were commenting about. I did a little bit of research on Grock here and Grock, you have to take it for what it is. It's not always accurate, but Grock mentioned that some key contributing factors to the differences in behavior may be the base OS software updates that are happening such as the driver monitoring system. Also, server side fleet learning updates and hardware specific optimizations and calibrations. And lastly, controller and planning refinements. It's really hard to know exactly what's changed without Tesla telling us.

[00:09:16]And now for V14, we just touch the screen and the car shifts into drive and then takes off. That is one difference is you can start self-driving from parkland, >> whereas with hardware 3, you have to put it into drive before you can start self-driving. There we go. It came to a full stop. There was the Nitsa stop also here on version 14.

[00:09:44]Nobody around, by the way, and it still made that full stop. It doesn't matter where you are. It always does that. Now, we're going to go around this curve and then get on the highway. Everything's going to be very, very similar. I am not expecting any differences to be honest with you. Both versions with version 14 and version 12, it doesn't matter.

[00:10:05]hardware 3, hardware 4. They both operate very similarly. So, if I use the right scroll wheel here, I'm in hurry mode. Now, there's MadMax. I'm going to go back to standard and keep it there.

[00:10:18]And it looks like standard does a good job keeping it at 40 m an hour. Five over. That's very safe. And I I I feel that's very comfortable. So, if I were driving and using this regularly, I would be using the standard speed profile.

[00:10:36]Let's just take a look at the version here. This car did get an update very recently. It is version 14.2.2.5 and this is 2026.2.9.1.

[00:10:49]So, some people ask the question, what's the difference between the full self-driving and what's called the software? Well, the software is the base OS and then the self-driving is on top of that. It's actually completely different from the base OS. The base OS includes the map updates. It includes the driver monitoring system algorithm and all of the normal operations of the vehicle.

[00:11:15]>> Whereas the self-driving is managing, you know, how it drives. It's using the neural nets and all of the AI. See, look at this. It got on the highway just the same as hardware 3. Again, I'm not expecting anything that's going to be different. I'm not expecting to touch the wheel. I'm not expecting to touch the accelerator or the brake.

[00:11:37]We are going to have to take over though to force it back to come back to that the residential neighborhood area. And here's a sideby-side comparison showing both of them getting onto the highway.

[00:11:48]You can see they both come to a stop.

[00:11:50]Well, hardware 3 does. It waits for those cars. This is perfectly in sync, but you're going to see hardware 3 is consistently about 10 mph faster than AI4. Now, I think this has to do with the speed profile. Hardware 3 is set to hurry mode, whereas AI4 is set to standard. It's really hard to tell, though, because there are only three speed profiles with hardware 3 and five with AI4.

[00:12:16]So, I'm going to do the same thing. I'm going to reroute as soon as we make this turn and take it back to the neighborhood.

[00:12:27]As we get back onto Interstate 94 here, I want to draw attention to how it takes these turns here. It's very, very smooth. The acceleration is great. The speed is fine. Everything here is really beautiful. I'm going to do a sidebyside comparison with this version and hardware 3 in a moment. Hardware 3 in the past used to have an issue where it would go to merge and if there was a car right next to you, it would basically barrel itself directly into the side of it. It was not very cool. Um, and this was documented so many times and never really fixed, although the latest versions don't really show that happening with hardware 3. So, here we are with the vehicle side by side. We come down this ramp here and you're going to notice the speed with hardware 3 is a little bit faster. It's moving ahead. Now, this could be because I have it in hurry mode, whereas with AI4, it's still in standard mode. It very well could be related here, but you can see hardware 3 is just a little bit faster at getting onto the highway here. And then look at the left turn signal. Left turn signal turns on right now on the hardware 3. and now with hardware 4. So, it's a little bit of a delay there. And look at the merge behavior. Hardware 3 gets over fairly quickly. I would say hardware 4 very similar. Now, from a day-to-day basis, hardware 3 works great. It really depends on the vehicle, though. Some owners have mentioned that their vehicle doesn't perform so well. Today, you're not really going to see any huge differences on this very simple drive.

[00:14:03]And it kind of goes to prove my point that hardware 3 is sufficient for the vast majority of owners out there. But it's important to understand the advantages of having hardware 4. First of all, it has a much more powerful computer that's roughly 3 to five times faster for inference. It also leverages full resolution video inputs from the cameras. Also, the AI compiler and the runtime have been basically rewritten with version 14.3. It was created using an MLIR. MLIR stands for multi-level intermediate representation and that's a new compiler that delivers 20% faster reaction times, smoother operation, and quicker model iteration.

[00:14:48]That just does not exist with version 12. Users and reviews describe version 14 as far more confident and natural.

[00:14:57]There are fewer hesitations at stops.

[00:14:59]There are better lane changes, reduced phantom braking, and smoother overall driving. It handles the full trip, including start and end maneuvers like garage exit and park more autonomously in many cases. Whereas version 12 can feel hesitant with issues like slow starts, inconsistent lane choice at lights sometimes, or navigation quirks.

[00:15:23]Now, the navigation quirks exist with hardware 4 owners as well on version 14.

[00:15:27]So, it's not like that's completely gone, but you definitely get a more premium, smoother experience with version 14 right now.

[00:15:42]And let's see how it gets over onto this side street here. Again, hardware 3 made a mistake once. I don't know about hardware 4.

[00:15:54]Okay, the light is green and it gets over just fine. Uh it in fact it was a lot more confident in getting in this straight lane. So that's a very good thing. Overall, I didn't touch the wheel, not even once on hardware 3 or hardware 4.

[00:16:15]I would say hardware 3 is really good for the vast majority of Tesla owners.

[00:16:22]It's extremely capable. It's end to end on highway and city streets. In other words, you don't really notice any sort of transition or any unusual behavior when it goes from one to the other. It's great for highway road trips. It's good for routine city street driving. and it has very impressive smoothness and uh overall minimal interventions under supervision.

[00:16:48]However, though, it's important to note that hardware 4 definitely is better. It provides better handling, especially complex scenarios, emergency vehicles, parking maneuvers. Uh there's just so many benefits of owning an AI4 car. In conclusion, this drive really didn't show too many significant differences between the two versions. I didn't have to touch the steering wheel, and I also didn't have to touch the accelerator or the brake pedal, intervene, or disengage even once. However, it takes quite a bit of driving to realize the significant benefits of using an AI4 vehicle. This is a very exciting time in history as we enter a new era of transportation. The future is being written as we know it, and it's such an exciting time to be involved. Thanks so much for watching and until the next one, have a great day.