example data:

oracle 11g sys, sh.sales 100k rows

SQL Server 2005 - AdventureWorks

select * from Production.TransactionHistory
select * from Sales.SalesOrderDetail
select * from Production.TransactionHistoryArchive
select * from Production.WorkOrder
select * from Production.WorkOrderRouting
select * from Sales.SalesOrderHeader
select * from Sales.SalesOrderHeaderSalesReason
select * from dbo.Full_Log
select * from Person.Contact
select * from Person.Address
select * from Person.newtest3
select * from Sales.CustomerAddress
select * from Sales.Customer
select * from Sales.ContactCreditCard
select * from Sales.CreditCard
select * from Sales.Individual
select * from Sales.CurrencyRate

DataCache.DATA_CACHE_ENABLED

enables data compressor which eliminates duplicate instances in the context of a single query.  This mechanism caches only immutable objects.

DataCache.NUMERIC_CACHE_ENABLED

adds static cache for small numeric values.  My testing shows that any benefit (if any) is undetectable.

Here is a typical test result - 2005/AdventureWorks/Production.TransactionHistory:

(first number is allocated memory at the end of the query, second - the max memory, third - allocated memory after gc cycle)

1. without any caching:

140/240/144

141/188/134

2. data caching only

90/157/82

89/152/82

3. with data and numeric caching

90/143/82

91/158/82

Both caching mechanisms are currently disabled.  Perhaps we should enabled them in 8.5 and do a PR campaign.