Answer by Harry Glinos for Quickest Method to Reverse in String in C#.net

The fastest way I have found to reverse a string in C# is with the following code. It's faster reading in 32bits at a time instead of a char's length of 16bits.In debug mode, it is faster until you get to about 93 characters. Anything longer than that Array.Reverse() is faster. Using a release build and running outside of the IDE, this method will blow Array.Reverse() out of the water at any string length.

char[] MyCharArray = MyString.ToCharArray();UIntStringReverse(ref MyCharArray);     //Code to reverse is below.string ReversedString = new string(MyCharArray);private static unsafe void UIntStringReverse(ref char[] arr){    uint Temp;    uint Temp2;    fixed (char* arrPtr = &arr[0])    {        uint* p, q;        p = (uint*)(arrPtr);        q = (uint*)(arrPtr + arr.LongLength - 2);        if (arr.LongLength == 2)        {            Temp = *p;            *p = ((Temp & 0xFFFF0000) >> 16) | ((Temp & 0x0000FFFF) << 16);             return;        }        while (p < q)        {            Temp = *p;            Temp2 = *q;            *p = ((Temp2 & 0xFFFF0000) >> 16) | ((Temp2 & 0x0000FFFF) << 16);             *q = ((Temp & 0xFFFF0000) >> 16) | ((Temp & 0x0000FFFF) << 16);            p++;            q--;        }    }}