Can we calculate the bandwidth for a CPU?

Solution 1:

I apologize for being too terse, in the comments. Let me expand a little bit.

The Intel link you provided states that your particular core can be served by two types of RAM, DDR3L 1333/1600. They operate at 1300MHz and 1600MHz, respectively. Assuming you have the faster one, you can transfer to one of them 64bits x 1600x10^6 times per second, which equals 12.8GB/s. However,the same Web page states that the core has (at most) two memory channels, so using both of them at the same time will allow you to reach the Max Memory Bandwidth of 12.8 GB/s x2 = 25.6GB/s, the final figure quoted in the document above.

An even more curious case is that of the i7-6700 processor, which can use, as memory banks, even DDR4-1866/2133, with 2 memory channels. Repeating the computation above, 8B per cycle, 2.133x10^9 cycles per second, 2 memory channels, you obtain 34.128GB/s, which jibes with the value in the link, 34.1GB/s.