Most benchmark tests try to take an all-things-equal approach: A single computer is set up and only the component being tested is changed. Sometimes this isn’t possible as some components require parts designed to work with them. This is mostly seen with video cards and SLI connections or processors and north bridge chips.
There are many minor factors that can affect a computer’s performance. In an ideal situation the test will cover programs you use most often; otherwise you’ll need to use your best judgement when trying to relate testing numbers to the end-user experience. It helps to understand how each component impacts speed.
Clock speed: This is the number of times an instruction can pass through a processor each second. As different ways of processing have been added this number has lost its meaning outside of processors with the same architecture.
Cores: Most modern CPUs have several cores. Each core acts like an individual processor, running its own instructions. Operating systems can spread out tasks among these cores for improved performance. Individual programs must be designed to split up their program to be shared among these cores. Those that aren’t can suffer a severe performance handicap as they can only be run on part of the CPU.
Memory: The CPU access memory through channels via the north bridge chip. While overlooked by most users, the difference between north bridge chips can affect total system performance by 5% or more. Most desktop systems will have a memory chip for each channel, but some laptops may only use one to save space, negatively impacting performance especially with memory-intensive graphics and video programs.
Graphics: Most video games are built on top of game engines. These engines tend to be optimized for a certain set of video processors making general graphics tests less relevant. Most video card charts include performance in frames per second (FPS) for games using prescribed graphics settings. Future games using the same engine will have similar performance.
Hard drives: Solid state drives have much faster seek and read times than traditional hard disks. SSDs are often the best bang-for-the-buck performance upgrade for low-end systems where time spend booting or loading programs is the most notable aspect of performance.