Heroes 3 on a dual-core processor.

Well, I don't know, but I can suggest updating your graphics card drivers and reinstalling the game. www.nvidia.ru And the processor really isn't the issue here.

Next, owners of AMD processors should download and install the AMD DualCore Optimizer program.

If, despite performing the actions described above, problems still occur during the game (freezes, crashes to the desktop, etc.), you should try to hard-bind the game to one of the cores. To do this, after launching the game, press Ctrl+Alt+Del, in the task manager that appears, right-click on the game, select Go to processes, then click again with the right button on the selected process and select Set affinity. In the window that appears, uncheck one of the cores, it doesn't matter which one, and then close the window, the task manager itself, and return to the game.

If, after the specified actions, the problems do not disappear, and you have an NVIDIA video card installed, you can try disabling multithreading optimizations in the video drivers. Launch the registry editor (Start -> Run -> regedit.exe), go to the address HKey_Local_MachineHardwareDeviceMapVideo and write down the address where the video card settings are located from the variable devicevideo0. Note that the specified address differs in Windows 2000 and Windows XP, in Windows 2000 it will look like \REGISTRY\Machine\System\ControlSet001\Services\nv\Device0, while in Windows XP \Registry\Machine\System\CurrentControlSet\Control\Video{DD18ED74-F584-4145-B29B-E3A6C6189FAA}\0000. Go to the specified address, keeping in mind that \Registry in this case indicates that the information is in the registry, and \Machine indicates that it is stored in the HKEY_LOCAL_MACHINE section. Click the mouse in the right part of the window, select Create - DWORD Parameter, name it OGL_ThreadControl and assign it the value 2. To disable multithreading in Direct3D applications, you need to create a variable WTD_EXECMODEL of the same type and assign it the value 0. [[COLOR="Red"Note that game developers usually react quite quickly to such problems, and before disabling dual-core support, it is worth checking if there is a patch for the game that fixes possible errors.

Added 17 minutes ago
Last time I was too hasty about the processor, I thought we were talking about the fifth game.