COMPTIA A+ Practice Exam 2026 – 400 Free Practice Questions to Pass the Exam

DDR3-1066 refers to the type and speed of the RAM. The 1066 refers to the rate at which data can be transferred per second in megatransfers (MT/s). Since DDR3 RAM operates at double data rate, the actual bus speed is twice the transfer rate. Therefore, to determine the bus speed, we need to divide the transfer rate by 2. In this case, the bus speed for DDR3-1066 is 533MHz.

Option A 400MHz is the bus speed for DDR2-800, not DDR3-1066. So it is incorrect.

Option C: 667MHz is the bus speed for DDR3-1333, so it is also incorrect.

Option D: 800MHz is the bus speed for DDR3-1600, which is faster than DDR3-1066. Therefore, it is not the correct answer.