ESXi v5.5 is having random crashes

You likely have a hardware problem. This is not an issue with VMware ESXi.

• Which build number of ESXi are you on?
• What firmware revision is the server hardware/BIOS on?
• Is the other ESXi host you mentioned comprised of the same hardware?

Your best bet is to examine the HP Integrated Management Log (IML) of the server. You can do this through the ILO 2 interface.

• Log onto the ILO, check the hardware system status tab. That main summary screen will probably tell you what's wrong.
• Additionally, take a look at the IML option under the "System Status" tab. This will tell you why the server crashed.

That's all. You may have a RAM, CPU or system board issue here.

Edit: Update your host's firmware, please!! - Don't become a statistic!

The download for the current bootable firmware DVD for your system is here. Please boot your system with that and let it update all of the components. Everything on that server looks like it dates back to 2008. That's a BIG no-no when working with HP server hardware.