I have an RPI3 and I wrote the image to the Samsung Ultra 128gb (SDSQUNC-128G-GN6MA) which was listed on the compatible cards spreadsheet on the retropie Wiki. Like the title says, I have major lag issues with Genesis, Turbografx, NES Atari, Master System, et al. The strange thing is that the functioning MAME games run full speed without issue. I thought it was possibly due to the CRT visual effects that are on this image but MAME has it and even the newer games run without lagging. Any one encountering this and resolve it? Thanks in advance to anyone taking the time to help me out!