SimCity on SNES gets faster maps, better saves and mouse support

The Super NES version of SimCity is getting a serious technical overhaul. SimCity SA-1 has now reached beta testing, and the goal is simple: make the game faster, smoother and less limited by the original cartridge hardware. The project uses the SA-1 enhancement chip, a processor that appeared in a number of later Super NES games. Instead of asking the console’s main CPU to handle almost everything, SimCity SA-1 can split the workload between two processors. That changes quite a lot. The city simulation can run faster, menus can stay more responsive and tasks such as generating a new map don’t need to leave the player waiting for several seconds. The project also plans changes to save data, information screens and controls.

The SA-1 gives SimCity more room to work

The original SNES processor has plenty to do while SimCity is running. It has to handle the interface, graphics, input and the calculations behind the city itself. As the simulation becomes busier, those limits become easier to notice. The SA-1 gives the game another processor to work with.

It’s based on the same 65C816 architecture as the SNES CPU, but it runs at 10.74 MHz. That’s considerably faster than the console’s main processor. In SimCity SA-1, the idea is to let the SA-1 handle much of the city simulation while the SNES CPU deals with the interface and other tasks. Both processors can work at the same time instead of waiting on each other. The result should be a game that reacts faster without changing what SimCity fundamentally is.

Simulation speeds become genuinely different

SimCity already has several simulation speed settings, but the SA-1 conversion pushes the faster modes much further. The slowest setting is intended to stay fairly close to the original pacing. The middle option increases the simulation speed without turning the game into a blur. Then there’s the fastest setting.

The project has targeted city calculations running roughly 10 to 20 times faster than the original game. The SA-1’s higher clock speed helps, but so does its arithmetic hardware, which can take over calculations that would otherwise require more work from the SNES CPU.

That should make long stretches of city development much quicker. If you’re waiting for population growth, tax income or other simulation changes, you shouldn’t have to leave the game running for nearly as long.

New maps don’t take forever to generate

Anyone who’s spent time restarting SimCity maps will understand this one immediately. The original SNES game can take around 10 seconds to generate terrain after you choose a map number. That’s not disastrous, but it becomes annoying when you’re checking several layouts in a row.

Early SA-1 versions cut that wait to about 2.5 seconds. The development target goes even further, aiming for generation times below one second. It’s a small change on paper. In use, it’s the sort of improvement you’ll notice every time you start a new city.

Mouse support is part of the plan

The project also aims to support the Super NES Mouse through the second controller port. You won’t have to use it. Standard controller support remains part of the design.

Still, mouse control makes obvious sense for SimCity. The series started on computers, and much of the game revolves around selecting tools, pointing at parts of a map and placing structures. Using a mouse could make the SNES version feel much more direct without changing the actual game underneath.

Information screens should load faster too

SimCity regularly asks the hardware to process maps, graphs and other city data. The SA-1 includes hardware that can help with bitmap processing, and the project has been exploring ways to use that for the game’s information displays. In suitable cases, processing could be around 20 times faster.

That could reduce the pauses that appear when opening certain statistical views. Other ideas include larger information maps and overlays displayed directly on the city screen. Those features have been discussed as part of the wider project, although not everything from the development plan has been confirmed for the current beta.

More flexible save data

The original SNES release gives players two save slots. SimCity SA-1 is looking at a different system. Instead of giving every city a fixed amount of storage space, the new design can compress save data and use the available memory more efficiently. That could allow more cities to fit into the cartridge’s backup memory.

The exact number hasn’t been locked down. The new format is also intended to store extra game information that the original save system doesn’t always restore properly. That should help prevent problems with things such as city rankings and zoned areas after loading a save.

The project has now reached beta

The biggest change isn’t another performance figure. It’s the fact that SimCity SA-1 is now running as beta software. The project reached that stage on 18 August 2026. A beta version has been made available to supporters while testing continues and bugs are checked. There’s no confirmed public release date yet.

What already stands out is the scale of the work. This isn’t just a faster ROM with a couple of timing changes. The project is redistributing processor workloads, changing how maps are generated, reworking save storage and exploring better ways to control and display the game.

If the planned features make it through testing, the result should be a noticeably quicker and more flexible version of SimCity on the SNES, built around hardware the original cartridge never had access to.