For ESXi compatibility, you just need to worry about the NIC and the Storage Controller mostly. If what you have in your hardware is on the compatibility list, then you don't need to worry too much if the unit as a whole is not. Even if the unit is a desktop, just give it a whirl. ESXi would be the best choice, and if drivers load, you'll be good to go. You would most likely have success if your machine is capable of booting from a USB stick. Most system I see beyond Pentium D have the ability to boot from USB. You can even install ESXi into USB so you can try it out before blowing away the local disk. I would even suggest installing and just running ESXi from USB full time. Lets you use all of the disk space for your guest machines.
I would only expect problems if you needed to call VMWare for support. It's about $800 last I looked to get support for the free ESXi Hypervisor, and support is limited (they kinda want folks to buy the full product). Once it is known that your hardware is not supported (if a support call gets to that), then you would only get best effort support (meaning they will try, but will ultimately give up if no solution can be found).
In going the Workstation route, it also has a cost that goes with it, though not very high. Do note, they only offer install and usage support. They do not offer production support for the Workstation product. A way to save some money; Build your guest machine in Workstation while it is in eval mode (you get 60days I think). Then you can just us Player to run the machine for free. Still no support from VMware, but you can also purchase Player Plus for $99 and get support. With all the bells as whistles they have been putting into Workstation, you also have the ability to build a guest in Player now as well.
So I would suggest trying ESXi if you can since it would give you the best performance for your guest machine at the lowest cost. Player would give you the low cost but will sacrifice performance to give you compatibility.
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Brent Schmidt Senior Network Engineer
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