What You Need to Know About Memory and CPU

What you need to know about RAM, memory, CPU Processing and other important stuff that could tell you why your computer is slow.

Physical RAM/Memory

RAM chips funcion quite literally like your Computer’s Memory. All the information that needs to be remembered when operating between different tasks (or even the same task) gets stored here. You know how people who have great memories can be awesome, that translates to the computer world as well, more memory = more awesome. So 8GB >> 4GB >> 2GB >> 1GB >> (this is 2011, don’t even consider anything less than 1GB).

Virtual RAM or Virtual Memory

Just like how humans can’t store everything in their head, there are times when some of the stuff has to be written down or stored as reminders. When your computer’s physical RAM or memory is full, it begins to offload some of the information onto a special space carved out of your hard disk (your hard disk is like a big notebook, you’ve generally got plenty of space here). This carved out area is called a swapfile or Virtual Memory or VM. VM, is hard disk space that can be used as memory and VM size indicates the amount of disk space currently being used as memory.

Paging out/Thrashing:

When you need to start writing everything onto your notebook, you’ve got a problem. You’re either not organized or you’re doing things too complex for your IQ to handle. In the computer world the process of writing stuff onto your virtual RAM is called Paging out or Thrashing. When you see too many page outs or thrasing cycles, you’ve got a problem because HDDs are much slower than RAM modules when calling back information (If you use solid state drives or SSDs, you’re going to see a marked performance difference. Even still, nothing like physical RAM). The number of gigabytes of information your operating system has moved between RAM and disk space is generally indicated by Page in/outs.

Page Out/Page Ins

Page out is the movement of data from RAM to hard disk and Page in is the movement of data from hard disk to RAM. Ideally you shouldn’t have any page outs.

CPU Processing

Physical RAM is the destination to store the temporary data, but the part instructing everyone around on which data to store and where, is the CPU. You can think of it as the actual brain. More GHz = bigger brain = more awesome. So a 2 GHz processor is generally more awesome than a 1.5 GHz processor.

CPU Processor usage

You won’t generally find your CPU processor usage peaked (if you do, you’ve got a problem). It’s ok to have spikes in your processor usage. These are the times when your computer’s brain is doing some heavy lifting, telling eveyone where to go and what to do. But if you find your usage constantly high, 100% most of the time, there’s some ugly memory leak going on that needs to be taken care of.

GPU Video card memory

For demanding games and other video graphics intensive processes, people generally have independent video cards that function like little CPUs themselves and have their own memory. The CPU part of a video card is called a GPU and the memory part is called -wait for it-memory. When doing heavy duty video editing, 3D graphics or games, you want a dedicated graphics card.

Real Memory

The amount of real memory a program is using at that instant. This is real memory used from your memory chips on the RAM module.

Free Memory

Good glorious free memory that is completely unused.

Wired Memory

Also knows as Resident Memory, the memory is locked or reserved and cannot be shared with other processes. OS/System processes, drivers, kernel code etc. tend to use this memory.

Active Memory

Memory actively being used. The Real Memory values mentioned earlier should sum up to this value.

Inactive Memory

Memory that has been used to cache disk I/O. You can think of inactive memory like free memory that’s been reserved for a recently closed application, but will be used when ‘true’ free memory has been exhausted. If you have 1 GB of memory (for the sake of making this discussion easier) on a freshly booted system, imagine the OS uses 300 MB and you open an app that uses 200 MB. You now have a total of 500 MB used, and 500 free. If you close that app that was using 200 MB, the memory is marked inactive and you’ll now have 300 used (OS), 200 inactive, and 500 free. If you open an app that requires 600 MB, it’ll use the free memory then pull from the inactive pool.

Used Memory

Wired + Active + Inactive. Nothing useful here, move on.