I am looking to purchase the 27in IMac 256gb or 512gb SSD with either 3.4 or 3.5 processor. So my question is will I see a great difference between the 3.4 vs the 3.5. I will be using it with Capture One Pro and FCP with 4k video. I will not be playing games on the computer. If have to wait 10 more seconds for the 4k video to render, no big deal. Also regarding storage. I will be putting all media on externals, so 256gb or 512gb? Thanks.