Disk taking long to load

When you initially formatted the disk, did you use a maintenance app that came with the disk to do so? If so, this may be the problem. Those maintenance apps almost always cause problems with Macs. Otherwise try running Disk utility's Repair app and see if that helps. Last, try doing a restart in the Safe mode. Hold down the Shift key on restart. The startup can take up to 10 minutes while the operating system is repairing itself and cleaning its caches, so be patient. Then, restart normally and see what happens.