File Reading operation....

If you are working with dynamic strings, format 2 will be faster. If you'll make something like constant size array for each record - it doesn't matter. byte[] rec = new byte[20000]; ReadData(rec); //filling array with record data and byte[,] rec = new byte[20,1000]; for (itn i = 0; i < 20; i ++) { ReadData(i, rec); //read 1000 symbols into rec[i,*] } are almost the same. but between this two ways: string rec = ReadData(); //reading whole record, not knowing it size at once and string[] rec = new string[20]; for (int = 0; i < 20; i ++) { rec[i] = ReadData(); //reading part of record, not knowing it size } second way is faster.