I got a question from @repping yesterday which got me thinking. His question was: "Do you know a good site where I can find memory prices for enterprise hardware.". Later it became clear he wanted to use that price to calculate chargeback for memory. He wanted to know the amount/GB. My fist reaction was: well, looking at the total amount of memory in combination with certain size DIMMs - the price rises with larger and larger DIMMs.
I think Dell uses a quite transparent site, with reasonable prices. Let's take a typical server, an R720 which can hold 2 XEONs and hold 24 DIMMs. Here is a table with the current price at time of writing this post:
Mr. @esloof did a nice tweet about this one and caught my attention. It's a very nice diagram in pdf format showing the memory management for vSphere 5. The thing I like best is the way it is set up: screenshot from esxtop, vSphere client and very clear mapping of virtual memory into physical memory. I'm printing it on A2 and stick it onto a wall and look at it from time to time. I suggest you do the same . Check it out here.