Dictionary vs Hashtable vs ConcurrtntDictionary for Registrations about container

[ENikS]

Test rig:

            object tmp;
            var size = 10000000;
            var data = new string[size];
            for (var i = 0; i < size; i++)
                data[i] = i.ToString();
            
            Stopwatch timer = new Stopwatch();

            var dict = new Dictionary<string, string>();
            timer.Restart();
            foreach (var s in data)
            {
                dict[s] = s;
            }
            timer.Stop();
            var dictAdd = timer.ElapsedTicks.ToString("000,000");
            timer.Restart();
            foreach (var s in data)
            {
                tmp = dict[s];
            }
            timer.Stop();
            var dictGet = timer.ElapsedTicks.ToString("000,000");
            dict = null;
            GC.Collect();
            GC.WaitForFullGCComplete();

            var conc = new ConcurrentDictionary<string, string>();
            timer.Restart();
            foreach (var s in data)
            {
                conc[s] = s;
            }
            timer.Stop();
            var concAdd = timer.ElapsedTicks.ToString("000,000");
            timer.Restart();
            foreach (var s in data)
            {
                tmp = conc[s];
            }
            timer.Stop();
            var concGet = timer.ElapsedTicks.ToString("000,000");
            conc = null;
            GC.Collect();
            GC.WaitForFullGCComplete();

            var hash = new Hashtable();
            timer.Restart();
            foreach (var s in data)
            {
                hash[s] = s;
            }
            timer.Stop();
            var hashAdd = timer.ElapsedTicks.ToString("000,000");
            timer.Restart();
            foreach (var s in data)
            {
                tmp = hash[s];
            }
            timer.Stop();
            var hashGet = timer.ElapsedTicks.ToString("000,000");
            hash = null;
            GC.Collect();
            GC.WaitForFullGCComplete();

[ENikS]

Number of samples is given in millions. Measurements are in Ticks.

Populating:

Implementation	1	5	10	15
Dictionary	338,422	1,946,961	4,136,670	X
Hashtable	582,512	6,013,090	X	X
ConcurrtntDictionary	2,013,063	12,647,402	27,715,503	42,819,408

Reading from:

Implementation	1	5	10	15
Dictionary	174,306	1,087,306	2,326,253	X
Hashtable	311,539	1,422,119	X	X
ConcurrtntDictionary	351,228	1,950,246	4,188,999	7,906,353

X - Means Out of Memory exception has been thrown.