No, there won't be any performance issues, windows can generally manage this stuff quite well.
Still if you want to make it a single partition, you have to delete both the partitions of "E" (backup the data first, of course ) and then create a new single partition. Also, you can't delete the 2nd E: partition(390gb, the one on the right), before the 100gb (one on left) because your E: partition starts from the 390gb partition.