What is the difference between TPC-C, TPC-E and TPC-H benchmark?

TPC-C (circa 1992) models an 'old school' OLTP application that looks like a wholesale distributor with a small number of warehouses full of inventory servicing a larger number of retail locations. In this context it measures 'transactions per minute' (tpmC). It assumes old-school IT architectures where DRAM is very scarce and as such it relies heavily on disk IO.

TPC-E is a modern OLTP application that models a stock brokerage and uses a much more sophisticated simulated world driven by fluctuating stock prices and emulates a chaotic 'outside world' of customers placing market orders, limit orders and stop-limit orders. TPC-E assumes modern IT architecture where DRAM and compute resources are more plentiful and therefore it does not rely as much on storage performance.

TPC-H is an OLAP workload that measures query analytics in a 'data warehouse' context.

In a nutshell, TPC-E is good for OLTP, TPC-H is for OLAP and TPC-C is basically obsolete.

This page is still available on internet archive and contains a good overview:

https://web.archive.org/web/20120919183401/http://www.tpc.org/information/benchmarks.asp