Custom Resolution Utility (CRU)

[Martik9]

I have bought an GTX 1660 Super and as some people know, NVIDIA disabled interlaced output from Turing, I read somewhere that using an secondary old AMD GPU like this Ati Radeon HD 6450 you can use the NVIDIA card as rendering one while you use the Ati Radeon as output, well, my motherboard doesnt have an second GPU slot so Im using a riser, I have installed both drivers, but before I uninstalled the old ones with DDU, after that plugged my two monitors into the Ati Radeon, seems to work but when I start playing or just play a video, it becomes very laggy and the Ati Radeon raises it's temperature, at the same time is like is sharing computational work with the GTX and makes performance horrible, any suggestion?

My idea is to use an Samsung CRT Syncmaster 796MB at 1600x1200i 100Hz