.NET HashTable Vs Dictionary - Can the Dictionary be as fast?

Question

System.Collections.Generic.Dictionary<TKey, TValue> and System.Collections.Hashtable classes both maintain a hash table data structure internally. None of them guarantee preserving the order of items.

Leaving boxing/unboxing issues aside, most of the time, they should have very similar performance.

The primary structural difference between them is that Dictionary relies on chaining (maintaining a list of items for each hash table bucket) to resolve collisions whereas Hashtable uses rehashing for collision resolution (when a collision occurs, tries another hash function to map the key to a bucket).

There is little benefit to use Hashtable class if you are targeting for .NET Framework 2.0+. It's effectively rendered obsolete by Dictionary<TKey, TValue>.

I guess it doesn't mean anything to you now. But just for reference for people stopping by

Performance Test - SortedList vs. SortedDictionary vs. Dictionary vs. Hashtable

Memory allocation:

Time used for inserting:

Time for searching an item:

Differences between Hashtable and Dictionary

Dictionary:

• Dictionary returns error if we try to find a key which does not exist.
• Dictionary faster than a Hashtable because there is no boxing and unboxing.
• Dictionary is a generic type which means we can use it with any data type.

Hashtable:

• Hashtable returns null if we try to find a key which does not exist.
• Hashtable slower than dictionary because it requires boxing and unboxing.
• Hashtable is not a generic type,

Another important difference is that the Hashtable type supports lock-free multiple readers and a single writer at the same time, while Dictionary does not.

MSDN Article: "The Dictionary<TKey, TValue> class has the same functionality as the Hashtable class. A Dictionary<TKey, TValue> of a specific type (other than Object) has better performance than a Hashtable for value types because the elements of Hashtable are of type Object and, therefore, boxing and unboxing typically occur if storing or retrieving a value type".

Link: http://msdn.microsoft.com/en-us/library/4yh14awz(v=vs.90).aspx