DirectDraw emulation still broken in Windows 10

I own a ASUS N64VM it has a Ivy Bridge CPU and a nVidia GeForce 630M

When I bought it, I didn't knew Optimus existed... and thought that it was a GeForce laptop... so the first thing I did was attempt to make DGPU work by default.

Currently it is set in nVidia Control panel to default to DGPU, all games are also set to high-performance, I used nVidia Inspector to set Optimis SHIM to default to DGPU (some games don't work without nVidia Inspector), and disabled Secure Boot in the bios (Age of Decadence and some other Torque3D and Ogre3D games break with nVidia Optimus if Secure Boot is enabled, I have no idea why).

So right now most games work with the DGPU as expected, but games that use DX1 to 8 doesn't properly.

In SimCity 4 case, it actually fires up the GPU, and seemly some (not all) draw requests are passed to it, but any information requests return the Intel GPU instead, thus the game breaks (ie: it attempts to use extensions, texture comrpession model, and whatnot, designed for the intel card, without realizing nVidia Card is helping).

Some other games (but I don't recall particular ones now) also do that.

Mind you, it is not a bug only of DGPU failure to work, but of the drivers (or DX, dunno who is the culprit) returning wrong data.

SimCity 4 has a very useful feature: it dumps the data it got from the Windows APIs when it launches.

here is what mine dumped:

driverName = nvumdshim.dll

driverVersion = 10.18.13.5560, GUID: D7B78E66-4226-11CF-F373-7734A6C2CD35

cardName = Intel(R) HD Graphics 4000

cardVersion = Vendor: 8086, Device: 0166, Board: 14771043, Chipset: 0009

cardIdentity = Intel(R) HD Graphics 4000

cpuSpeed = 2294

memory = 1024

freeMemory = 1024

screenWidth = 1280

screenHeight = 1024

screenBPP = 16

videoMemory = 32

textureMemory = 32

textureStages = 4

bogoFPS = 0

bogoMPPS = 0

The CPUSPEED came from RDTSC, and is wrong (when SimCity 4 launched, RDTSC counted CPU Cycles, Microsoft + Intel decided to create invariant RDTSC that return a arbitrary count, and created no "legacy" mode, thus all games taht expect RDTSC to count cycles get wrong data, my cpu actual speed is 3.3ghz)

memory is incorrect (it is 8gb, but since this is a 32bit app it should get 3gb at least...)

free memory also incorrect.

screen width and height, is correct (I set my desktop on purpose to the resolution that the game supports, to make it run less buggy).

screenBPP incorrect (should be 32... Windows 8 and 10 don't even support 16!)

VRAM incorrect, erroneous data came from Intel Chip (Intel HD4000 reports 32mb vram by default, because it uses the computer normal RAM as its main RAM).

texture-memory, same thing.

texture stages, also incorrect (Intel chip has 4 texture stages, nVidia I think has 8+)

I have no idea what is bogoFPS and bogoMPPS

I tried many, many, many different things, including reinstalling drivers, installing ASUS OEM drivers, installing Intel and Nvidia drivers, compatiblity modes, administrator, non-administrator, editing compatibility in the registry, and so on. these numbers never changed.

the only thing that change: if I disable "high performance" in the nVidia control panel, the driver change from nvumdshim.dll to igdumdim32.dll

And if I use some wrapper (like Wine, or DgVoodoo2) then all the video-related info change, but not always correctly either.

I'll have SimCity 4 looked at on a hybrid graphics laptop. I see you have an Ivybridge CPU, what is the graphics card? Which nividia chipset?

Also, If you go into the geforce control panel and set the GPU to "High Performance.." does that fix the game from running off of the Intel?

Oki, i would like to use win 10, but what preventing me, it's one game, which work perfect up to win 7. From win 8-10 i had a lot trouble to use it on normal way, so to make it short, Kevin: could you look intro Turok 2 Seeds of Evil (use demo if you not have full game, near hands) and you should find that fps is locked on magic ~33 fps, fps limit that showing us, that, something is wrong in core... Game using dx 6.1. Please help me, ty, and of course i, myself, will keep testing to find can some dll or registry key show truth, how to unblock magic fps limiter for many old games, which are plagued on exact same way. Greetings.

I found out why SimCity 4 behaves even worse than it already do in Win 8 and 10 when running on a laptop with nVidia Optimus, I am not sure if the bug is in nVidia Drivers, Intel Drivers or in DD emulation.

SimCity 4 queries about the video card using the function IDirectDraw7::GetDeviceIdentifier

The MSDN page https://msdn.microsoft.com/en-us/library/windows/desktop/gg426144(v=vs.85).aspx says that if it is called with the flag DDGDI_GETHOSTIDENTIFIER it should return the information about the Host video card, while with the flag "0" it should return the secondary video card.

SimCity 4 uses the flag 0 (ie: it requests the secondary video card).

When DirectDraw was made, and GPUs were mostly completely optional separate hardware, the "host" card was whatever came in the motherboard, and the "secondary" was the video card (usually inserted in a PCI/AGP/PCI-E slot).

With switchable GPU laptops, it is logical to expect that the "host" should be the GPU integrated in the CPU (example: Intel HD 4000 that comes in my i7) whiel the "secondary" card should be the discrete GPU chip.

SimCity 4 on my machine requests the secondary card, but gets the host anyway... when it attempts to get the host, it also gets the host, meaning that the function GetDeviceIdentifier always return the Intel video.

I have no idea who is the culprit here, probably it is nVidia (they said around in 2008 or 2009 in press conferences that they had no intention of supporting DirectX 1 to 8)

But maybe it is a DDraw emulation bug, so I would appreciate if you took a look (even better if you push the fix to Windows 8 too)