Install ESXi 5 to USB, which stick to use

I would recommend and use Hewlett Packard (manufacturer PNY) or Sandisk 4GB flash drives.

There is no point in using a performance based flash drive, the flash drive is only used to read the contents of the tgz files, which are then extracted and run from memory (machine memory), the only other time, the USB /SD card is used is to read the VMware Tools (isos), occasioanlly the contents of configuration is written back on machine shutdown.

2GB is adequate, but we've always used 4GB for installation.

Cheap versus Branded, is just a longevitity issue, but we've only ever had one fail, after many years of service.

Here is the VMware KB on installing 5.0 on USB/SD:
http://kb.vmware.com/kb/2004784

How to Backup an ESXi installation on an USB Flash Drive or SD card, for security or redundancy.

you can even remove the USB/SD card after the files are read to prove that ESXi still runs without an USB/SD card installed!

Video - VMware vSphere 4.x (ESXi) does work when you remove the USB stick!

Also note, plastic bodies flash drives are also better, to reduce the risk of shorting or static damage to motherboards.

http://andysworld.org.uk/2011/07/31/a-micro-flash-hp-v165w-drive-for-a-hp-proliant-microserver-n36l/

Sandisk Cruzer blade drives are all plastic and very small.

Write speed to them is quite slow though. Not sure if it would matter much here.

What about hanccocka s post?!!

You don t need the usb after boot so prob. speed usb is only for boot?!

I want to clarify this from Hanccocka. I don't have experience running esxi from USB.

What s the difference between usb on motherboard and usb external? My hp microserver has  one, but perfectly boots from usb plugged in on external usb slot.

I guess none functionwise. Just the position.

Motherboard bsed USB are usually designed to have priority over other USB ports, and are single ports, not bus multiple port based.