Graphics Card's proximity to Firewire Card causes noise on connected audio interface (by firewire)

Question

I am doing some amateur audio stuff where I have an audio interface connected via firewire to my pc. After my former machine got old, I replaced it and unfortunately bought a cheap motherboard. It has neither firewire nor wifi, so I had to buy both as pci cards.

Now I have a similar thread about having massive problems working with audio related to wifi (Can WiFi interfere with FireWire PCI card?) which resulted in disabling the wifi adapter.

But now I realized that I still have annoying clicks while simply playing a wav file (via the firewire audio interface) that makes it impossible to judge whether the click is in the actual audio file or not.

After removing all cards and disabling processes I realized that when I disable my GeForce GT 640 in the device manager the clicking absolutely stops. (My drivers are up to date)

I've tested two firewire cards, both showed same behaviour.

The firewire pci is next to the video card pcie slot and I just moved the firewire pc as far as possible, the result is far fewer clicks (but still unusable).

Disabling gpu fixes the problem, but result in a crappy rendered desktop. The board has an onboard gpu but I need to switch it in the bios so "quickly" doing some audio processing is virtually impossible as the workflow to disable PCIe card, reboot and switch to the onboard is less than straight forward.

The machine is not a dedicated DAW, therefore I sometimes need the real graphics card :)

I am curious what effects this. Improper shielded cheap video card? General voltage issue?

Edit: I can approach this on a serious level like creating an etl again, but last time it showed me just that there were DPCs from some nvidia driver, which caused me to update my drivers but I did not know how to dig deeper into that.