doady

Low occupancy is a reflection of low desirability rather than low population. For any building, residential or commercial, if you increase desirability it will increase the amount of occupants. You don't need 120k jobs for 120k population. It's more like 1:2. My current city has 190k people, 110k jobs, no problem. But even so, the amount of employment land will be disproportionately high compared to residential land. Job demand can be fulfilled easily enough even with the low max occupancy of industrial buildings, so mods that increase double or quadruple industrial occupants may have unintended effects, and completely unnecessary anyways from a pure gameplay perspective. Ultimately, the game is in an unfinished state, and only so much we can do about the bugs and unbalanced gameplay. The issue with high density is even one new building can fulfill demand too fast, and thus create negative demand. Looking at your city, I don't see any obvious corridors for commercial zones. This is also one of the central tenets of Transit-Oriented Development: minimizing the distances of residents and jobs to major corridors. Establishing strong corridors means carefully zoning and laying out streets and major roads. One important thing to note is intersections increase travel times, so assuming you have any pathfinding fix installed (such as NAM), commuters will naturally gravitate to major corridors that have fewer intersections. Likewise, you can find ways to make it less convenient to travel on side streets.

Maybe you hit the demand caps? Have you built and any neighbour road/rail connections, recreation facilities, etc?

These is a mod to make SimCity 4 use 4GB RAM instead of 2GB, which makes a noticeable difference. Unfortunately, there is no way to make the game take advantage of modern multi core processors, so performance will suffer with large cities no matter what. I play physical copy of the game in Windows 7 64-Bit, Phenom II, 8GB DDR3, 1GB Radeon 7850 no problem so I can't imagine your setup will have any problem either.

I should elaborate further on the problem here, because I finally understand it: My city has a big subway system, with all the stations are combined with road-top bus/subway stations. All except ONE. And that lone stand-alone subway station the only point where the sims enter the subway system in the morning, and the only point where they exit the subway system in the evening. The road where this lone stand-alone subway station is located has a whopping 1200+ pedestrians where people are transferring from a nearby stand-alone bus station! That means that the residents of my city are using far-away bus/subway stations to get on the bus to transfer to this one lone stand-alone subway station to get onto the subway, when they should have instead just gotten on the subway at the bus-subway station! This means that I have to use separate road-top bus and subway stations to have a properly functioning subway system, which is a hassle because there has to be 1 tile space between them. However, this is still much better each bus and subway station taking up 1 tile on its own, so I still like this road-top addon very much.

Even before using Road Top Mass Transit, I have always placed bus stations beside elevated rail and subway stations with no problem. And if the simple presence bus stops is supposed cause subways to have zero ridership (which makes no sense), then the creator of Road Top Mass Transit should get rid of all the combined bus-subway stops from it.

It appears that, while my sims can access bus service from the combined bus/subway stations, they cannot access the subway service from those very same stations. The result is that entire sections of my subway system has ZERO riders, despite those same subways are underneath roads that are heavily congested with cars and buses.