If i can't switch between 2 video cards in my bios. There is another way to do it? Maybe software that do this? Maybe some advanced tool? Maybe somehow add this possibility to my bios? or Maybe replace the bios (if it's possible)? Or anything you can think of?
If one was extremely determined and had an electronics background, they could sever specific traces to the PCIE 16x slot to make it optional at boot. Or a custom 90 degree PCIE 16x riser board engineered up that would allow for this. But the problem is that its going through extreme effort to get this to work, and for most its way far and beyond the time and money to make this a reality. I work as an electronics technician for example and I have done hardware modding of electronics, but to me I would go the easier route in running it on a different box vs wasting time and money to alter the way that your computer handles the video card.
As far as severing devices without having to physically remove devices, I made up a breadboard with two USB ports once and a relay that ran off of the 5VDC. This allowed via a toggle switch selection of using one bootable USB stick over another. The USB sticks were inside of a server that was locked that ran an altered Live Linux OS configuration. The toggle switch mod to swap between USB sticks was added so that a power user at the site could enter the server room, shut down the server. Flip the toggle switch and boot the server. The server would then run off of the other Live Linux OS off the other healthy USB stick. For most people if a USB stick got corrupt, just pop it out and pop in the other. But we needed strict controls on all external USB ports disabled to avoid unauthorized USB sticks, and this board I made internally to flip 4 pins from one USB stick to another prior to boot was the solution and had very little power draw to pull off. Now with this I was only dealing with switching over 4 pins to pull this off. For you to pull off enabling and disabling a PCIE 16x slot you would need to sever a good majority of the pins starting to the PCIE 16x power pins, then data and address line pins if a card in the slot that is not powered pulls down the bus since a video card not powered may inadvertently become a load on the bus since its no longer powered. I have never tried such a mod. It could be done if all the right pins/traces are severed prior to boot or reconnected prior to boot. But its a large project and if it were me, id just grab another computer to run tails on.
So to answer if it could be done... answer is YES, But only with a serious PCI Express 16x slot mod by a professional who knows their way around electronics and wants to buy lots of costly relays as the safest passive method of disconnecting and connecting the PCIE 16x connections between the motherboard and the video card. Relays can get costly with a DPDT 5 Volt or 12Volt relay in the $2.50 range each, and a DPDT relay can only sever 2 pins, so for my project I had 2 DPDT ( Double Pole - Double Throw ) Relays to swap between 2 USB sticks. The issue with lots of relays is that the coil load of all of them on the 5V or 12V or load balanced among both 5 and 12V relays used for switching of enabling or disabling of 2 pins each could load down the PC power supply and overwhelm it, so while I used the 5V from a P-connector inside you might even need a power supply separate from that of the computers power supply to drive this. Additionally one very primitive form of switching would be to add a massive turn type switch that is long and bulky with individual contacts to break and connect the connections between the video card and the PCIE 16x slot mechanically teamed. These switches are very costly.
Here is an idea of how many connections you would need to break and connect to disable and enable the video card in the PCI Express 16x slot. The GND ( Ground ) pins you dont need to worry about and I would keep connected at all times so that the video card is properly grounded and not floating ground at any point to protect it from Static Discharge. I think you can see how wildly overkill a mod of the PCIE 16x slot is to be able to enable and disable the video card.
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