Clevo M540, M540N, M545N, M550N, M555N Motherboard Schematic Circuit Diagram
Clevo M540, M540N, M545N, M550N, M555N Motherboard Schematic Circuit Diagram
Cache Performance and Design
Most L2 caches, like the L1 cache, have a hit ratio of around 90%; as a result, when you look at the system as a whole, it works at maximum speed (233MHz in our case) 90% of the time by accessing data from the L1 cache. The retrieval of data from the L2 cache slows down 10% of the time. The CPU travels to the L2 cache 90% of the time because the data is in the L2, and 10% of the time because of an L2 cache miss, it needs to go to the slow main memory to obtain the data. As a result of combining the two caches, our test system runs at full processor speed 90% of the time (233MHz in this case), motherboard speed 9% (90 percent of 10%) of the time (66MHz in this case), and RAM speed approximately 1% (10 percent of 10%) of the time (16MHz in this case). Both the L1 and L2 caches are critical; without them, the system will frequently use main memory, which is substantially slower than the CPU.
This raises a number of interesting points. Which would you enhance if you had the option of spending money to double the performance of the main memory (RAM) or the L2 cache? Given that main memory is only accessed directly approximately 1% of the time, doubling performance there would only double your system's speed 1% of the time! That doesn't seem like a significant enough improvement to warrant the investment. On the other hand, doubling L2 cache performance would result in a 9 percent increase in total system performance, which is a significant improvement. I'd prefer to enhance L2 performance than RAM performance. A similar argument may be made for expanding the amount of the L3 cache, as many current AMD and Intel CPUs have done.
