In early 2023, Tesla launched its FSD Hardware 4.0 – now known as AI4 – an improved version of Hardware 3 with various advantages. This hardware launch initially came off to a rocky start with FSD and Autopilot not being available to freshly delivered vehicles.
Today though, AI4 is the next step as Tesla strides towards full autonomy. While Tesla hasn’t abandoned HW3 or declared it as legacy yet – and doesn’t seem to plan to, it’s still important to be able to figure out what hardware your vehicle has. This is especially true for those who have paid for, or are subscribed to FSD – as it seems that going forward, AI4 will receive major FSD updates before hardware 3, which will require optimization.
So, let’s go over what AI4 offers in terms of improvement, the fact that there is no retrofit path from Hardware 3, and finally, a few easy ways to tell FSD Hardware 3 from Hardware 4/ AI4.
HW4 / AI4 Improvements
AI4 brought along several improvements, including new cameras, new electrical and wiring harnesses, and most of all – improved processing power.
The new cameras bring improved resolution for better details. The rear camera on AI4 has a resolution of 1448x938 vs 1280x960 on Hardware 3. However, there’s a much larger differences in the front cameras. HW4/AI4 has a resolution of 2896x1876 while HW3 has a resolution of 1280x960. That’s a huge improvement in quality - additionally, that telltale red tint that they have ensures better performance in low-light conditions. The video below compares the difference between HW3 vs HW4.
Musk previously said that HW4 is about 3-5x faster than hardware 3, although all of that compute power isn’t being utilized yet. We’ll likely see the full power of HW4 come into play with the divergence of HW4 later this year.
How to Tell If You Have HW3 or HW4 / AI4
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If you have access to the inside of the vehicle, the easiest and surefire way of determining the FSD hardware of a Tesla is to check in settings. As of software update 2024.38, Tesla has added the ability to view the vehicle’s hardware version. To see simply go to Settings > Software and then tap Additional Vehicle Information.
In the list of options, you’ll see ‘Autopilot computer’, followed by the FSD computer hardware version. You’ll likely see version 2.5, 3 or 4.
If You Don’t Have Access to the Vehicle
Note the telltale red glint of the HW4 cameras
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You should still be able to tell what version of the FSD computer is in the vehicle even if you don’t have access to the inside of the car. There are a few several ways to tell if you have Hardware 3, or HW4.
Delivery Date
The first is based on your model and delivery date. If you purchased Model S or X, you’ll likely have AI4 if you purchased after March 2023. If you have a Model Y, it’s after late May 2023 for vehicles made in the United States. The updated 2024 Model 3 has HW4, but if you have a 2017-2023 Model 3, you’ll have Hardware 3.
Red Camera Lenses
Next, if you’re not sure of the delivery date of your vehicle, or want to confirm, take a look at the vehicle itself. HW4/AI4 has cameras with red lenses – the easiest place to see this is on the front cameras – where there will be 2 red lenses and one black (fake) lens. AI4 got rid of the 3rd front-facing camera since the cameras now have a higher resolution.
The repeater cameras are also slightly different, with the same red tint, but include a smaller and narrower turn indicator.
HW4 (top) and HW3 (bottom) repeater cameras
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No Retrofit to HW4
Elon Musk and Tesla have confirmed that unlike AP 2.5 or AP 2, Tesla does not intend to offer a retrofit for older vehicles. This isn’t a surprising move, especially given the fact that there is an entirely new wiring and cooling harness for the compute unit in AI4.
This, in turn, with AI4’s different form factor, means that upgrading HW3 vehicles to AI4 isn't feasible. A retrofit would be a complex and expensive task that would likely require building a custom solution that would fit into HW3 vehicles. It also comes with other complications, such as overwhelming Tesla Service. Instead, Tesla will continue to do it the software way – by optimizing and updating the FSD models to perform well on Hardware 3.
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Tesla has unveiled its 6-seat Model Y variant in China, known as the Model Y L. This new variant of one of the world’s best-selling vehicles comes with a longer wheelbase, adjusted C-pillar design, and most importantly, a six-seat interior layout.
The vehicle’s specifications have been officially listed in a filing with China’s Ministry of Industry and Information Technology (MIIT), confirming a launch for this fall.
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The addition of a longer wheelbase and a more spacious third row is a fantastic addition for the Model Y’s family utility, and positions this variant as sort of a mini Model X, but let’s compare the sizes to really know how this new Model Y compares to a Model X.
Meet the Model Y L
The defining feature of the new Model Y L is its six-seat configuration. This layout has previously been exclusive to the larger and more expensive Model X. While Tesla has offered the Model Y in a 7-seat configuration before, the third row was much too small to be utilized by anyone but small children.
Comparing Model Y L to the Model X
@xiaoteshushu on X
Let’s compare this upcoming Model Y L to the regular Model Y and the Model X.
Vehicle/Dimension
Wheelbase
Overall Length
Model Y
2,890mm / 113.8 in
4,797mm / 188.9 in
Model Y L
3,040mm / 119.7 in
4,976mm / 195.9 in
Model X
2,965mm / 116.7 in
5,060mm / 199.2 in
The new wheelbase of 3,040mm is a significant stretch from the standard wheelbase, and in fact, is longer than the Model X’s wheelbase of 2,965mm. However, the overall length of the vehicle is 84mm (~3 inches) shorter than the Model X. This means the vehicle sits neatly between the current Model Y and Model X, filling a much-needed gap.
While this Model Y L is slightly smaller than the Model X, it doesn’t necessarily mean that it’s smaller inside. The Model X features a much larger front end than the Model Y, accounting for several inches. When you line up the front wheel base of the Model X with this new Model Y, the vehicles are almost exactly the same length.
Tesla has designed this Model Y to be a bit more compact and efficient than the Model X, and likely much cheaper, while featuring the well-loved design of the new Model Y.
Other Specifications and Price
The MIIT filing also provided a detailed look at some additional specifications. The Model Y L is a dual-motor, AWD variant, so it will likely be more expensive than the current Model Y AWD that’s available in China today. Tesla charges an additional $6,500 USD when upgrading the Model X from a 5-seat configuration to a 6-seat layout, so we may see something similar here.
The extra length has been added behind the C-pillar, resulting in a longer rear profile for the Model Y L. To accompany this, Tesla has added an updated rear spoiler, similar to the one found on Performance variants, but not carbon fiber. There is also a new wheel design to complement the updated look, along with unique Model Y L badging and a new light gold paint option.
In classic Tesla fashion, no Tesla is slow - and the Y L has a 0-100 km/h (0-60mph) time of 5.9s, with a top speed of 217km/h. Alongside an 82.5 kWh LFP battery pack, the Model Y L boasts an impressive CLTC range of 688 km (427 mi).
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Launch & Availability
According to posts from Tesla China on Chinese social media, the new Model Y L is scheduled to launch in the fall of 2025. Its official listing in the MIIT database is essentially the final regulatory step required before sales can begin, which means the launch is really just around the corner. For now, it appears that Tesla intends to launch this vehicle only in China, as no other filings have been made in other regions. However, these could be revealed in the coming months.
The new Model Y L is a huge addition to Tesla’s lineup - one that addresses the Chinese preference for vehicles with longer wheelbases and additional passenger room in a compact SUV package. The question is - will this variant make its way to North America and Europe?
Solving real-world artificial intelligence - whether for autonomous driving, real-world robotics, or advanced reasoning - requires an almost unfathomable amount of computational power. To meet this challenge, Tesla has been developing its own custom AI training hardware while simultaneously purchasing hardware in the open market.
Now, the next-generation Dojo 2 chip has reportedly entered mass production with the world’s largest semiconductor manufacturer, TSMC. While many may consider this a side quest, expanding Tesla’s computing base will be necessary to achieve exascale supercomputing, which will be crucial for all of Tesla’s AI ambitions.
Elon Musk called Dojo 2 “a good computer,” and then followed up with a classic computer performance joke - Dojo 2 can indeed play Crysis at a billion frames per second.
While Tesla has effectively utilized powerful third-party GPUs to train its models to date, the Dojo supercomputer is a ground-up, application-specific solution designed for a single purpose. It will efficiently process massive amounts of video data for training neural networks. The Dojo 2 chip itself is the key that unlocks this potential.
Dojo 2 will train the vision-based neural nets that FSD relies on, allowing Tesla to process video from its massive global fleet of vehicles even faster. As Tesla continues to improve FSD, one of the biggest challenges has been the intake of video for handling difficult edge cases.
Hundreds of thousands of miles of training data may pass by before an edge case is identified and trained on, but it all needs to be analyzed, labeled, and processed, which is key for Dojo 2. Each new useful piece of training data will help Tesla proceed down the march of 9s, making FSD just that little bit better every time.
This process requires massive amounts of compute and training time - but it is an absolute necessity to improve FSD. Of course, this goes beyond just FSD in vehicles. Tesla’s humanoid robot, Optimus, also runs on FSD to navigate and interact with the physical world.
While it may be a custom version of FSD, it remains FSD at its core, which means the same neural nets that analyze the environment and build a 3D map of the world for your car perform the same work for Optimus.
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Custom Approach to AI Hardware
Dojo 2’s power doesn’t just come from raw compute; it comes from a series of architectural choices that make it excel at training FSD and differentiate it from general-purpose hardware, or even other AI-specific hardware.
To this end, Tesla is using TSMC’s new Integrated Fan-Out with Silicon-on-Wafer (InFO-SoW) packaging technology. For massive AI workloads, heat and the speed at which data moves between chips are often the biggest bottlenecks.
This new packaging technique allows for high-bandwidth connections directly between processing dies, which lowers latency and dramatically improves heat dissipation, all key to building massive and dense compute clusters.
Unlike general-purpose chips, Dojo 2 is designed with a custom instruction set, specifically built to train FSD. The cores are specifically made to accelerate the exact mathematical operations, like matrix multiples and systolic arrays, which form the backbone of Tesla’s vision-based neural networks.
By building its own hardware, Tesla can then integrate its own software and compilers directly with the silicon, optimizing for specific workloads and avoiding the performance penalties that can result from using third-party software, such as Nvidia’s CUDA.
The start of Dojo 2 may seem like a side quest for some, but it’s actually a key step for Tesla’s AI technologies that give them an advantage over the competition using off-the-shelf hardware. They’ll need to continue investing in custom hardware to improve FSD at a reasonable pace, rather than the current glacial pace we’ve seen over the last few months.