How to understand the maximum throughput of intel core 2 quad q8300?

Question

Iron

The system bus frequency is 1333 MHz.
That's all that is written on the site.
If I put 800 in dual mode 12800 mb / s - will it completely fill? In general: help me understand how to calculate the maximum throughput of the processor with ram in dual mode.

Answer 1

In those ancient times, the memory controller was in the northbridge, the northbridge communicated with the CPU via the FSB bus.
FSB is a 64-bit thing in the days of core 2 quad, effectively quadrupling the frequency of the base oscillator, 4 chunks of data are transferred per clock - that's why the marketing decided to call it 1333 MHz instead of 333 MHz (which is in reality).
the memory is also on a 64-bit bus, at twice the frequency of the base oscillator. DDR2-800 - 400MHz bus. Two channels - respectively 2 buses of 64 bits.
In total, if you are only interested in the bandwidth - a simple mathematical calculation turns out that there is no point in putting the memory with a frequency higher (and, accordingly, a 1: 1 divider). Two memory channels at twice the frequency of the base oscillator (2 * 2 * 64 bits) just correspond to the capabilities of one FSB at a quadruple effective frequency (4 * 64 bits).
But at the same time, this may make some sense if you look at latency. You won't be able to pump more data - FSB is limiting, but you will be able to get data from RAM with less latency.