[SpookyZalost]

Thinkpad or something? Extremely based, I'm jealous.

well I do have an old thinkpad with both serial and parallel ports but for my desktop I picked up the add on card at microcenter, so far works in both linux and windows 8.1

Yeah you can get a lot more transfer if there was a better kind of port to actually connect the device to handle multiple pins.
Since your laptop has an RS232 port, maybe you can try to use the standard library RS232 arduino headers or something. Either that or just use raw UART or something along with a converter because either way, if you do most of the work on the device itself instead of having to wrap everything in IBUS over serial and wait for vJoy to parse and use data (and entirely eliminating the middleman of SerialFeeder) then your polling rate will probably be exponentially higher than 40Hz.

Looks like DirectX also includes Joystick drivers with some relatively open source documentation on how to use it. Seems it uses COM objects on the HID stack, so it'll probably also be a lot faster than vJoy, but IDK if it supports other ports than USB. In any case, would probably be much faster than the UJI 'stack' since it'll operate natively on Windows without the need for third-party tools.

But even I don't have any experience with DirectX since my graphics programming knowledge is next to zero from some guides I followed for OpenGL. And DirectX looks a lot more complicated. This is if you're hardcore, not really a weekend project xd

this right here is how I use my parallel port to plug in old video game joysticks lol.

basically just programming the parallel port to act as a gpio and making a cable that sends the connection pins to the parallel bus since those old joysticks are just that, custom parallel connections and such, each button going to a different pin.

honestly I wouldn't know where to begin making a 25pin parallel version of the current USB 4.0 bus, but if it were possible the data speeds would be insane, enough to crush thunderbolt and possibly sata... the only problem is, CPU bandwith, you'd need one hell of a southbridge to run it, and any add in cards would have to use PCI-E X8 possibly up to X16 to maintain it.

the question is, what would you use such a parallel bus for?

linking motherboards?

neural interface?

maybe some kinda plug n play NPU?

personally I'd find some way to expand it into a ton of custom user interface controls taking advantage of the huge bandwidth to have near zero latency.

also just came up with something dedicated for the linking motherboards bit.

High Speed Parallel Fiber channel bus.
Specifically designed for linking 2 or more core systems together in a cluster configuration, possibly for a neural network.

probably already exists though... and way overkill for mere joysticks lol.