System Performance

Jack V. Briner, Jr.

Computer Consulting Services

System Performance

The first thing people think of when they think about performance is the CPU. However, this is not always the problem.

What you need to know is that everything is connected. If your interaction with memory is slow, the fastest CPU will make little difference.

This is the real killer of most machines. If you don’t have enough RAM, the RAM contents are pushed out to disk (paging). Why is that bad? Well if 4 times is slow for CPU versus memory, what do you think of 10,000,000 slower that your disk is compared to memory.

Think of it this way: your kid says “just a second” to clean his room; however, it really takes about eight months. Now imagine everything taking eight months! That is the difference between RAM and virtual memory.

How do you make things better? For some systems, the easiest solution is to buy more RAM. However, mother boards do have limits as to how much RAM can be installed.

Another solution is to ensure that there are no unnecessary programs running. Every running program must have the RAM because the CPU cannot talk to the disk directly. As different programs run they may push other programs RAM to disk which causes them have to be reloaded from disk later when they run.

If you have too many of these processes fighting for RAM, you have what is known as “thrashing.” With thrashing, all of the programs are trying to run but none of them have enough RAM to do their job.

Your machine has different types of memory but most likely it is the RAM that can be one of the biggest bottle necks.

If you have a 2 GHz processor, that communicates to memory at 1/2 a GHz, valuable time can be wasted. Fortunately, a “cache” of memory exists on your CPU. So, get a big cache.

CPU

Virtual Memory

Memory (Random Access Memory—RAM)