Cheapest solution for target display mode in 2016

[elvispreasley2010]

Hello, people! Now I'm building my simple PC for using it only with one purpose - to connect to it old SCSI Imacon film scanner. But I also have one requirement, that makes this "project" not so simple in the meaning of the achieving the existing goal with minimal budget - PC needs to be connected to my iMac 21.5" (2011), using the last as an external display with help of target display mode.
My iMac is running latest El Capitan, so (as far as I know) the graphic card in my PC should have minidisplay port for connection. Indeed, during the last 3 days of researches, I found here and there some information that there is kind of graphic cards, which are works perfectly in target mote, using DVI-MDP and DP-MDP adapters. Sadly those threads were active in 2010-2011 years, when the Macs were under Snow Leopard and Lion OSX, so there is zero guarantee that they will work same good with EL Capitan.
So, I will be really appreciated for your help with advice of 100% working graphic card for my purpose. Performance doesn't make any difference for me! Main requirement is "as cheap as possible") Best solution will be some old (2010-2014) used card, but I will be happy for another options.
Really counting on your generous help!

p.s: I'm planing to run my PC, with searched graphic card, under Windows 7 (or OSX Tiger, if its possible to install - with latest OSX - Imacon Scanner software simply not working)

 

[Fl0r!an]

Starting with 2011 generation, iMacs do not accept DisplayPort inputs for Target Display Mode, but need a Thunderbolt connection (which no graphics card can output).

Using a mainboard with TB support might work when using the iGPU. Never tried that myself though. Personally I'd dump the iMac and get a standard display.

EDIT: Regarding your film scanner, have a look for the "VueScan" software. It's available for all OS and supports an enormous amount of scanners.

 

[elvispreasley2010]

Starting with 2011 generation, iMacs do not accept DisplayPort inputs for Target Display Mode, but need a Thunderbolt connection (which no graphics card can output).

Using a mainboard with TB support might work when using the iGPU. Never tried that myself though. Personally I'd dump the iMac and get a standard display.

EDIT: Regarding your film scanner, have a look for the "VueScan" software. It's available for all OS and supports an enormous amount of scanners.

WOW! That's absolutely amazing news! You seems to be right: I just checked the requirements for target display on Apple site and it says, that iMac mid 2011 (exactly what I have) using thunderbolt port for target display mode! Does anyone can confirm, that motherboard with TB port will be enough to successfully enter target display mode with my Mac?
Thank you for your advice regarding VueScan, but my scanner its not supporting by it - to old (but still very good and useful).

 

[elvispreasley2010]

Well, my further researches gave me an answer to my question - there is no way to use target display mode with windows pc on thunderbolt macs. Ended up with purchasing Powerbook G4)