The creative and talented team over at Munro Live has shared some exciting new information about Tesla’s highly anticipated HW4.
Last month, Tesla hacker and owner Greentheonly leaked photos of the HW4 computer, citing a myriad of new features and improvements. The new computer will allegedly be 2-4x faster than HW3. A portion of this computing power will likely go toward processing additional data from the upgraded 5MP cameras.
Along with the upgraded 5MP cameras come some additional changes that make it hard for Tesla to retrofit HW4 into previous vehicles. The layout of the HW is quite different and, as noted in Munro Live’s video, the board is significantly larger, among other things.
The Power of Tesla
One thing in particular the Munro & Associates team uncovered was that Tesla removed the separate graphics card and integrated it directly onto the MCU circuit board. The Munro team said this would increase performance by removing the communication bottleneck between the two boards. Furthermore, this integration will save Tesla around $2 per vehicle due to removing some small parts and it will help streamline manufacturing.
Not Only for Cost Savings
This speaks volumes about the power and manufacturing abilities of Tesla. While $2 per vehicle isn't a big deal on its own, the cost savings alone, which are expected to be up to 4 million dollars this year, will more than pay for the engineering time spent on making these changes. However, the bigger win will come in having fewer parts to handle and assemble when building a vehicle. It will also help increase the vehicle's reliability by having fewer failure points.
The AMD-powered infotainment processor is unchanged in HW4, but the processor utilized for taking the input from the cameras and sensors is now larger and received a performance boost. Tesla is expected to transition all vehicles to hardware 4 this year, including the upcoming Cybertruck (new Cybertruck features uncovered at Investor Day)which is expected to begin manufacturing this summer.
Tesla vehicles are equipped with two main computer systems: the MCU (Media Control Unit), which is responsible for entertainment and display functions, and the Autopilot/FSD Unit, often referred to as the FSD Computer.
Both of these systems have evolved over the years, and they’re commonly referred to by their generation. For example, MCU 2 refers to the second generation of the Media Control Unit. Similarly, the FSD computer is identified by its generation, often called Hardware 3 or Hardware 4, when referring to the third and fourth-generation hardware. More recently, Tesla has started referring to the FSD Computer as AI3 and AI4, but you’ll still hear the older terms used interchangeably.
These two systems are separate and they’re not upgraded at the same time, meaning it’s possible to have a vehicle with MCU 2 and FSD Hardware 3 or MCU 3 with Hardware 3. Some vehicles even feature MCU 1 alongside Hardware 3.
The MCU is not involved with Autopilot or FSD functions—it’s purely for infotainment and in-vehicle features such as vehicle visualization, gaming, maps, and entertainment. It doesn’t impact the capabilities or limitations of Tesla’s autonomous driving systems.
MCU 1 - NVIDIA Tegra 3
MCU 1 was the first media control unit to be introduced in Tesla vehicles, starting back in 2012. This system was used in the Model S and Model X until about April 2018, when Tesla began transitioning to MCU 2.
By the time the Model 3 launched in late 2017, it already included MCU 2. To keep legacy vehicles up to date, Tesla offers an infotainment retrofit that upgrades MCU 1 to MCU 2, which helps make the infotainment unit much more responsive and adds a variety of newer features. Tesla continues to support vehicles with MCU 1, although upgrades are much further apart. In 2024, Tesla added Automatic Emergency Braking (AEB) improvements to vehicles with MCU 1 and even support for FSD V12.3.6 (FSD HW3 required).
Period Offered: 2012 through April 2018
Upgrade: Available as a paid upgrade for Model S and Model X vehicles to go from MCU 1 to MCU 2.
MCU 2 - Intel Atom
The launch of the Model 3 introduced MCU 2, which ran on Intel’s Atom mobile processor. While the Intel Atom was capable at the time, it’s now considered outdated compared to modern standards. As Tesla continues to roll out new features, the limitations of the Atom processor have become more apparent.
There is a notable list of features that are unavailable to vehicles with MCU 2. Although Tesla has optimized software to improve compatibility, not all features have been made accessible to these vehicles.
Period Offered: MCU 2 was offered in 2017 (Model 3) through 2022 (availability differs based on region and model).
Upgrade: As of now, Tesla has not offered an upgrade path or retrofit to transition from MCU 2 to MCU 3, and they’re unlikely to do so.
MCU 3 - AMD Ryzen
In December 2021, Tesla began shipping vehicles with MCU 3, powered by AMD’s Ryzen processor. The first vehicles to feature MCU 3 were the refreshed Model S and Model X, which debuted in 2021. Shortly after, Model 3s and Model Ys were also equipped with MCU 3, and today, all Tesla vehicles, including the Cybertruck, come standard with MCU 3.
This MCU is now the most widely used on the road and is Tesla’s most advanced infotainment processor. It supports impressive 3D visualizations, allows improved gaming on the center touchscreen (and rear screens in equipped vehicles), and offers a host of other capabilities. MCU 3 is also the most feature-complete version, with new features being designed for it first and then backported to MCU 2 or MCU 1 when possible.
Period Offered: The first MCU 3 vehicles were released in December 2021 and is current through today.
Upgrade: MCU 3 is the most current infotainment unit that Tesla offers.
Features Missing on MCU 2 (Intel Atom)
High-fidelity park assist is limited to vehicles with MCU 3
Not a Tesla App
While Tesla does its best to continue to support MCU 2, there is a growing difference between the features available on a vehicle with an Intel Atom infotainment unit and one with the AMD Ryzen processor.
Feature
MCU 2
MCU 3
Games / Arcade
⚠️ Limited Games*
✅ Additional Games**
Parked View
⚠️ Split screen visualization with vehicle on left and map on right
✅ Full-screen Parked Viz - Shadows, Sun Reflections, Shadows
Vehicle Visualizations
⚠️ Some limitations, such as non-transparent glass
Improved UI for Display Modules - Media, Next Turn, Trip Planner
⚠️ Solid Color/Semi-Transparent
✅ Transparency + Background Blur for Display Modules
*Many recent game additions are available to MCU 3 only, including the ever-popular Vampire Survivors and Castle Doombad. Only certain Model S and Model X vehicles include a GPU and the ability to play games on Steam.
Identifying which MCU your vehicle has is straightforward. Simply go to Vehicle Options > Software > Additional Vehicle Information.
In the interface, you’ll find details about whether your vehicle is equipped with an Intel Atom (MCU 2) or AMD Ryzen processor (MCU 3).
MCU 4?
It’s been more than three years since Tesla introduced the AMD Ryzen-powered MCU. Despite advancements, including the transition from FSD Hardware 3 to AI4—and eventually AI5—there’s been no indication of an MCU 4 on the horizon.
The Ryzen processor’s impressive capabilities make it a solid choice for infotainment, and it’s well-suited to serve until there’s another big leap in CPU performance.
While Tesla will upgrade to MCU 4 at some point, it doesn’t seem imminent. Some may argue that Tesla transitioned to MCU 3 too late, leaving vehicles just a few years old feeling outdated. It’s possible Tesla might choose to introduce MCU 4 ahead of the need for more processing power, ensuring that older vehicles can continue to benefit from new software features in the future.
Following the surprising return of the turn signal stalk on the refreshed Model Y, reliable Tesla source Chris Zheng has indicated that the Model 3 will also be receiving a turn stalk. While it initially seems surprising, Tesla mentioned that after receiving lots of customer feedback, there is a lot of demand for the return of the stalk.
For those who appreciate the newer turn signal buttons on vehicles like the Cybertruck, this might come as a surprise. However, the Model 3 and Model Y are designed for the average driver transitioning from a traditional vehicle, making the removal of the turn signal stalk an unexpected and potentially disappointing change.
Turn Stalk
In a conversation during the latest episode of Jay Leno’s Garage, Tesla’s VP of Vehicle Engineering, Lars Moravy, mentioned that Tesla works to remove superfluous parts. In this case, they removed one part too many - and are now bringing back the turn signal stalk.
The updated stalk on the refreshed Model Y is a simplified version of the current Model Y stalk. It doesn’t include multi-stage turn signals (short three flashes versus staying), buttons, or other features. Pure and simple - it is utilized for signaling left and right. The rest of the functions of a traditional stalk remain either on the wheel or on the screen.
Lack of Right ‘Shifter’ Stalk
Tesla has no intent to bring back the right stalk, which is traditionally used to shift the vehicle from Drive to Reverse and Park in Teslas. It’s also used to activate Autopilot. The shifting functionality will remain on-screen or available via the backup by tapping the buttons on the ceiling near the hazards button. Shifting via the dash is intuitive and convenient once you get used to it - and with AutoShift hopefully coming out of Beta sometime soon, this could get even better.
Autopilot activation will remain with a button on the steering wheel. While a vehicle with a single stalk may look a little odd at first, Lars mentioned that Tesla didn’t receive many complaints about shifting or Autopilot use.
Retrofit
Not a Tesla App
We haven’t heard anything about retrofitting the 2024+ Model 3s with the turn signal stalk at this point. However, we imagine this may be a possibility in the future.
However, we can recommend using the wireless Enhauto’s S3XY Stalks if you want to bring a single or dual stalks back to your refreshed Model 3 and don’t want to wait for an official retrofit to arrive. They’re easy to install, well-designed, and reliable.
Other Models
The big question now is: will Tesla bring back the turn signal stalk for its other models? It’s possible, but we doubt it. The Model S and Model X, especially with the Yoke, feel more natural without a stalk, and the button-based signals suit their design. While a stalk might occasionally be useful—like signaling in and out of a roundabout—any future refresh of the S or X would likely include steer-by-wire instead.
On the Cybertruck, the absence of a stalk goes unnoticed, thanks to steer-by-wire, as the squircle steering wheel is never in an awkward position. After thousands of kilometers of daily driving, including plenty of roundabouts, the author can confidently say the signal stalk isn’t missed at all. In fact, the turn signal buttons feel more intuitive, given how the Cybertruck handles.
That said, could Tesla offer signal stalks as an option for those who prefer them? It’s not out of the question. We’ll keep you updated, but in the meantime, let us know—do you prefer turn signal buttons or a traditional stalk?
