As Tesla continues to push the capabilities of its hardware as it prepares for autonomy with FSD Unsupervised, there has been a distinct divergence in features between HW4-equipped vehicles on FSD V13, and HW3-equipped vehicles on FSD V12.6.
There are definitely reasons for this, and Tesla hacker Greentheonly, over on X, went into great detail on some of the reasons why this divergence has continued and is likely to continue.
If you’re interested in some background, we recommend the following articles. Although they’re not necessary, you may enjoy reading them before diving right in if you enjoy this topic.
Back in the summer of 2024, we reported that Tesla’s HW4 had yet to reach its full potential, and that HW3 still had some compute to work with. However, FSD has undergone a rapid evolution - there are now fundamental differences driven by the hardware capabilities and sheer scale of the latest builds of FSD.
FSD V13’s Gargantuan Neural Networks
FSD V13 is a substantial leap for Tesla. It features substantially larger neural networks - the core brain that processes all the environmental data and makes decisions. Those networks are far larger in V13 than in V12, which results in a much smoother and human-like expereience.
Tesla’s FSD computers contain two nodes. According to Green’s analysis of FSD V13, Node B, which handles the actual end-to-end driving logic, tripled in size from 2.3 GB in V12 to a staggering 7.5 GB in V13. That’s a substantial increase, and one of the main reasons why HW3 can’t handle FSD V13. While Interestingly, Node A on HW4 remains similar in size to FSD V12, using up about 2.3 GB.
However, this massive size is also pushing the limits of HW4. While this isn’t necessarily a big problem immediately - at the end of the day, there is a limited amount of compute and ram available and model sizes will likely grow in the future. In fact, Tesla is planning to scale model sizes in the next FSD version and has already said they’ll need to optimize them, as context size is limited by on-board memory.
HW3 Limitations
Since HW3 can’t run the latest FSD models, where does this leave millions of Tesla vehicles equipped with the now-legacy FSD hardware? Are they hitting a dead end? Not exactly - Tesla has promised to replace HW3 computers with new units during the Q4 2024 Earnings Call, but only for those who have purchased FSD and only if Tesla is no longer able to update HW3 vehicles.
There’s no doubt Tesla hopes to achieve autonomy and then work backwards to make it compatible with HW3, but that’s unlikely to happen with the limited ram available on HW3.
Tesla’s AI team has continued to say that they’re still working on updating HW3 vehicles - but that they will be taking a backburner to updates for HW4 until the team can optimize the model efficiently enough to run on the smaller footprint. That means V12.6 isn’t just V13 “lite” - it is a distinctly different software branch tailored specifically for HW3’s capabilities.
Green's analysis showed that HW3 under V12.6 runs NNs totaling 1.2 GB on Node A and 3.1 GB on Node B, which is significantly smaller than the footprint of V13. Back in November, we discussed how Tesla is running a smaller and optimized FSD model on HW3, with the specific goal of achieving similar performance to V13. FSD V12.6 appears to be the current implementation of that smaller model strategy.
Green also found that of the total neural nets used for FSD, 135 are shared between the current V12.6 and FSD V13.2 releases, which is the result of Tesla’s AI team working to optimize and refine the V13 model for HW3. So some neural nets are shared between the two sets of hardware, while others are specific to HW3 or HW4.
AI4 in the Future
The fact that V13 is already stretching HW4’s limits makes us wonder about Tesla’s imminent release of AI5. Last year, Tesla mentioned that AI5 would be 18 months away - which is now about 8 months away, and potentially even sooner to help solve the autonomy problem.
At the same time, Tesla is looking to launch Unsupervised FSD in June in Austin, Texas, with presumably HW4, which would indicate that they’re confident in its capabilities.
Unless Tesla launches the Robotaxi network with AI5, we don’t believe AI5 will be a “must have” item. Undoubtedly, it will result in similar improvements to HW4 compared to HW3. However, the software needed to take advantage of the newer hardware could still be years away.
All eyes will be on Tesla’s Robotaxi network launch and the hardware required for it. For now, HW4 owners are in good hands with future updates are on the horizon, and we’re certainly excited for what’s next.
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Tesla’s Dan W Priestley attended the Advanced Clean Transportation (ACT) Expo in Anaheim, California, and provided an update on Tesla’s Semi truck program. The presentation covered several key developments on the status of Tesla’s Nevada Semi Factory, refinements to the Semi, and Tesla’s plans for charging and ramping production through 2026.
Let’s dig in and take a look at everything that was captured by the Out of Spec team at ACT Expo. The original video is embedded below if you’d like to watch it.
Semi Factory & Production Ramp
Priestley reaffirmed the timelines mentioned during Tesla’s Q4 2024 Earnings Call that Tesla will scale Semi production in 2026. To achieve this, Tesla has been actively building and expanding the Gigafactory Nevada site, specifically to support the production of the Tesla Semi. The dedicated Semi facility will have a targeted annual capacity of 50,000 Semi trucks.
Following the beginning of production, Tesla will utilize the initial trucks to integrate into its own logistics operations. This will serve as both a final real-world testing ground as well as an opportunity for Tesla to gather data internally. Tesla plans to begin subsequent customer deliveries throughout 2026 as the ramp-up continues.
Reuters also reported that Tesla is hiring over 1,000 new employees at the Semi Factory to begin the rapid ramping of the program.
Semi has already amassed 7.9 million miles with Tesla’s current testing and operational fleets, providing some real-world data and testing. Feedback for the truck has been exceptionally successful, with many drivers praising the Semi’s performance and comfort.
New Tesla Semi Features
Of course, it wouldn’t be a Tesla keynote without showing off some new things. The Semi will be available in 500-mile and 300-mile range configurations, now featuring updated mirror designs and a drop-down glass section to improve visibility and allow easier interaction with external elements—such as control panels at ports, for example.
New Electric Power Take-Off (e-PTO)
The Tesla Semi will also feature a new capability called Electric Power Take-Off, or e-PTO system. Similar to the PTO systems found on other vehicles, this will allow the Semi’s high-voltage battery to power auxiliary equipment at variable voltages. That includes being able to power things like climate-controlled reefer trailers, potentially replacing the noisy and polluting diesel generators traditionally used for this purpose.
Charging and Batteries
Out of Spec BITS/YouTube
Tesla is also working on an updated battery pack design for the final production design of the Semi. This new pack is designed to be more cost-effective to manufacture. The battery pack itself is slightly smaller than before, but the truck maintains the same level of range through efficiencies. Dan also confirmed during his keynote that the battery cells for the Semi will be sourced domestically inside the United States, helping to alleviate potential burdens due to tariffs.
On the charging front, Tesla is using MCS - the Megawatt Charging System - capable of 1.2MW - and designed specifically for Semi. The system uses the same V4 charging hardware found at Supercharger sites but focuses on that larger power output. Alongside a smaller physical footprint, Tesla will be able to configure these V4 cabinets for either dedicated Semi charging or for shared power scenarios with regular Superchargers. Tesla is also working on an integrated overnight charging product, but Tesla isn’t ready to talk about it yet.
46 Semi Charger Sites Coming
The 46 new MCS sites coming soon.
Out of Spec BITS/YouTube
Finally, Tesla has made substantial investments in a public charging network for the Semi. There are currently 46 sites in progress throughout the United States, and plans for significant expansion throughout 2026 and 2027. These sites are strategically located alongside major truck routes and within industrial areas to support long-haul and regional operations. Tesla is aiming to offer the lowest possible energy costs to operators to help incentivize adoption.
This was one of the best updates to the Tesla Semi we’ve received since its initial unveiling. It seems that the Semi will receive a big portion of Tesla’s attention in 2026, while Robotaxi and FSD Unsupervised take the stage this year.
The Tesla Semi has the potential to transform transportation even more dramatically than EVs already have, serving as a testament to Tesla’s mission to electrify the world.
Sentry Mode is an invaluable tool for owners - capable of keeping the vehicle safe and secure even when you’re not around. This is especially true in recent times, with the misguided and unfortunate incidents surrounding Tesla ownership, including damage to Tesla vehicles, showrooms, and Superchargers.
B-pillar Camera Recording and Dashcam Viewer
With the 2025 Spring Update on 2025.14, Tesla is expanding Sentry Mode’s functionality for certain vehicles with some much-needed changes. Sentry Mode and Dashcam can now record footage from the vehicle’s B-pillar cameras. These cameras are located on the side pillars of the vehicle, between the front and rear doors.
This adds two crucially needed viewpoints, making Tesla’s Sentry Mode a truly 360-degree security system. These cameras also provide the best angles for capturing license plates when parked, so they will be greatly appreciated by owners in the event of an incident.
These vehicles are also receiving an improved Dashcam Viewer, which now displays the six camera feeds along the bottom and a new grid view. It also allows users to jump back or forward in the video in 15-second increments.
However, to the disappointment of many owners, not all vehicles are receiving these updates due to the additional processing power needed.
Limited to Hardware 4 Vehicles, Ryzen Isn’t Enough
We have confirmed that Tesla is only adding the additional camera recording and improved Dashcam Viewer on hardware 4 (HW4 / AI4) vehicles. The newer hardware presumably has the additional processing power and bandwidth needed to handle recording and saving the two additional video streams during Sentry Mode and Dashcam.
For the time being, owners of HW3 vehicles are not receiving this feature. This includes all vehicles with HW3, even those with AMD Ryzen infotainment systems. If you’re not sure whether your vehicle has HW3 or HW4, you can refer to our FSD hardware guide.
While there’s no doubt that recording two additional camera streams would be more computationally intensive, we hope that Tesla adds the improved Dashcam Viewer to HW3 vehicles in a future update.
Cybertruck Also Missing Improved Sentry Mode
Surprisingly, and most confusing for many - is the fact that the Cybertruck is also not receiving the improved Dashcam Viewer and B-pillar camera recording with this update. This struck us as odd, especially since the Cybertruck is currently the only vehicle with the improved, more efficient version of Sentry Mode.
Every Cybertruck is equipped with HW4 and AMD Ryzen infotainment units, so this clearly isn’t a hardware restriction. It’s possible the more efficient Sentry Mode is playing a role here due to the infrastructure changes. However, we expect Tesla to address this in a future update and eventually release these features for the Cybertruck as well.
Given the Cybertruck’s high visibility and its status as a frequent target for both positive and negative attention, many owners hoped that the Cybertruck would be one of the vehicles to receive this feature.
Adaptive Headlights
Tesla finally started rolling out its adaptive headlights in North America. While the new Model Y already came with the feature when it was released last month, other vehicles with matrix headlights are now receiving the feature in the Spring Update.
All vehicles with matrix headlights are receiving this feature, which includes the new and old Model 3, first-gen Model Y, and the new Model S and Model X.
If you’re not sure if your vehicle includes matrix headlights, check out our guide. What’s interesting here is that older vehicles that were retrofitted with matrix headlights due to an accident or user replacement are also receiving the adaptive headlights feature.
Legacy Model S & Model X
As with most updates, the older legacy Model S and Model X are not receiving all the features included in this update. Unfortunately, some of the features, which include the Blind Spot Camera on the instrument cluster, Save Trunk Height Based on Location and Keep Accessory Power On are limited to the new Model S and X.
Legacy S and X models will receive the Alternative Trip Plans feature, Avoid Highways (Requires Intel MCU) and the Keyboard Languages feature.
These vehicles are also receiving all the features in the Minor Updates section except for the visualization showing how far the door is opened, which is exclusive to the Cybertruck. These additions include improved music search results, contact photos in the phone app, automatic connecting to hotspots, the ability to show third-party chargers, view Supercharger amenities, and various improvements to music services.
While many users will be disappointed not to receive the B-pillar camera recording and Dashcam Viewer improvements, it’s important to remember that Tesla typically does a great job at bringing features to older vehicles, at least with the Model 3 and Model Y. If a feature isn’t added, it’s usually due to a hardware limitation.
![Tesla Semi Keynote: New Features, 46 Charging Sites, Upgraded Battery & More [VIDEO]](https://www.notateslaapp.com/img/containers/article_images/semi/semi-new-features.jpg/c7df4e0d32f8cb0beee080ad201e943b/semi-new-features.jpg)
