On a VPS you are limited resources such as CPU/RAM... A single VPS Server hold multiple VPS Nods (Clients), where as on a Dedicated you can use all hardware to its maximum limit.
A virtual private server (VPS, also referred to as Virtual Dedicated Server or VDS) is a method of partitioning a physical server computer into multiple servers that each has the appearance and capabilities of running on its own dedicated machine. Each virtual server can run its own full-fledged operating system, and each server can be independently rebooted. A dedicated hosting server is a type of Internet hosting where the client leases an entire server not shared with anyone. This is more flexible than shared hosting, as organizations have full control over the server(s), including choice of operating system, hardware, etc.
hi agree with Tosting as well. A VPS is great to a certain degree but when you need to fuel those intensive sites, there is nothing better than a ded. server.
Dedicated Server - 1 Piece to 1 customer VPS - Divide a dedicated into x no. of pieces, each one belongs to one customer. Assume you've got a cake only for yourself, thats a dedicated server. When you divide the cake in equal pieces and share with others, thats a VPS.
I like the way you described that inworx, I think houses make a slightly better analogy though. A VPS instead of a dedicated server is like living in a duplex instead of a house at the most basic level, or a condo instead of a duplex in more realistic situations.