Hi, i have a 2017 iMac 21.5. By default there was a 1TB Fusion drive installed. I replace the Blade SSD on the Board and the Hard Drive. I installed a Samsung Evo 970 Pro and a Samsung 860 Evo both 512GB. On the 970 I install MacOs and on the 860 is a copy of Windows. Speedtest under MacOS offers the Mac adress only 2 Lanes on the 970s. Read an Write Speed are approximately 1500MB/s. Does the mac have only 2 lines?