From ESXi 5.0, if you install ESXi to a empty hard disk, the target disk will be prepared with GPT-based partitions. That may cause some boot delay or even boot problem in some desktop motherboards.
Fortunately, you can use MBR mode instead of GPT.
1 Make a clean hard disk for ESXi. You can use any method to delete all partitions on that disk.
2 Boot with ESXi CD. During initial installation step, press Shift-O (letter, not number zero) when prompted (right down corner).
3 Type a space and “formatwithmbr” (without quotation marks). Press enter.
4 Go on setup. ESXi will make the target disk prepared with MBR-based partitions instead of GPT.