What does cpu cache do

The tag RAM is a record of all the memory locations that can map to any given block of cache. If a cache is fully associative, it means that any block of RAM data can be stored in any block of cache. The advantage of such a system is that the hit rate is high, but the search time is extremely long — the CPU has to look through its entire cache to find out if the data is present before searching main memory.

At the opposite end of the spectrum, we have direct-mapped caches. A direct-mapped cache is a cache where each cache block can contain one and only one block of main memory. This type of cache can be searched extremely quickly, but since it maps to memory locations, it has a low hit rate. In between these two extremes are n- way associative caches. An eight-way associative cache means that each block of main memory could be in one of eight cache blocks.

The next two slides show how hit rate improves with set associativity. Keep in mind that things like hit rate are highly particular — different applications will have different hit rates. So why add continually larger caches in the first place? Because each additional memory pool pushes back the need to access main memory and can improve performance in specific cases. Each stair step represents a new level of cache. Larger caches are both slower and more expensive.

At six transistors per bit of SRAM 6T , cache is also expensive in terms of die size, and therefore dollar cost. The more RAM your system has, the more programs you can run at once without affecting performance.

This is especially true if you participate in memory-intensive activities like video streaming and gaming. Your CPU will also factor heavily into how well your computer performs. An Intel or AMD processor is the best way to go. If you merely want to pick up performance, more RAM is one of the easiest ways to give your computer a pick-me-up.

Older PCs often will only go as far as DDR3, so you may need to invest in older modules if you want to stay with your current motherboard. Stephanie Faris is a novelist and business writer whose work has appeared on numerous small business blogs, including Zappos, GoDaddy, 99Designs, and the Intuit Small Business Blog. She worked for the State of Tennessee for 19 years, the latter six of which were spent as a supervisor.

She has written about business for entrepreneurs and marketing firms since How Important Is a Processor Cache? By Stephanie Faris Updated April 23, How to Enter Setup on an Acer Aspire. L1 cache — This is the primary cache. It is typically embedded in the processor chip. L2 cache — Also known as secondary cache, L2 cache can either be embedded on the processor chip or on a separate chip with a high-speed bus that connects it to the CPU.

L3 cache — This processor cache is specialized memory that can serve as a backup for your L1 and L2 caches. It may not be as fast, but it boosts the performance of your L1 and L2. The latest CPUs will naturally include more CPU cache memory than older generations, with potentially faster cache memory, too. One thing you can do is learn how to compare CPUs effectively. There is a lot of information out there, and learning how to compare and contrast different CPUs can help you make the right purchasing decision.

When the processor is looking for data to carry out an operation, it first tries to find it in the L1 cache. If the CPU finds it, the condition is called a cache hit. It then proceeds to find it in L2 and then L3.

When that happens, it is known as a cache miss. Now, as we know, the cache is designed to speed up the back and forth of information between the main memory and the CPU.

The time needed to access data from memory is called "latency. L1 cache memory has the lowest latency, being the fastest and closest to the core, and L3 has the highest. Memory cache latency increases when there is a cache miss as the CPU has to retrieve the data from the system memory. Latency continues to decrease as computers become faster and more efficient.

In that, the speed of your system memory is also important. Cache memory design is always evolving, especially as memory gets cheaper, faster, and denser. He enjoys copious amounts of tea, board games, and football. So, exactly how important is CPU cache, and how does it work? The more L2 and L3 memory available, the faster a computer can run. However, smartphones and tablets are generally not used to do intensive tasks like playing the most hi-spec advanced games.

Design - smartphones and tablets combine their processing architecture into a system on a chip SOC.