The 4-partition limit is an issue on disks that use the old Master Boot Record (MBR) partitioning system. Computers that ship with Windows 8 almost invariably use the newer GUID Partition Table (GPT), which has a much higher limit -- 128 partitions by default, although that can be raised with the right software. (Even MBR-based disks can have more than four partitions, but one of the four primary partitions must be an extended partition, which in turn can hold an arbitrary number of logical partitions. Getting this set up on a system that already has four primary partitions can be a pain.)
If you've re-installed Windows, or if your system came with Windows 7 and you subsequently upgraded to Windows 8, it's conceivable you'll have to deal with MBR's 4-primary-partition limit. If you want to be 100% sure of what you've got, you can check your partition table type, as described here.