How Much Memory Is Enough?
The rule of thumb for all computer systems to determine whether it has enough memory is to look at the requirements of the software you intend to run. Check the website for each application and the OS that you want to run. Find out the minimum and recommended requirements. More RAM than the highest minimum and at least as much as the highest listed recommended requirement is ideal. The following chart provides a general idea of how a computer will run with various amounts of memory:
Minimum: 4 GBOptimal: 8 GBSmooth Sailing: 16 GB or more
The ranges provided are a generalization based on common computing tasks. It is best to check the requirements of the intended software to make the final decisions. Some operating systems use more memory than others.
Does Type Really Matter?
The type of memory matters to the performance of a computer. DDR4 has been released and is available for more desktop computers than ever. Many computers that use DDR3 are available. Find out which type of memory is used on the computer, as it’s not interchangeable, and it is vital if you plan to upgrade the memory in the future. Typically, the memory is listed with the technology used and either its clock speed (DDR4 2133 MHz) or its projected bandwidth (PC4-17000). Below is a chart detailing the type and speed in the order of fastest to slowest:
DDR4 3200 MHz or PC4-25600DDR4 2666 MHz or PC4-21300DDR4 2133 MHz or PC4-17000DDR3 1600 MHz or PC3-12800DDR3 1333 MHz or PC3-10600/PC3-10666DDR3 1066 MHz or PC3-8500DDR3 800 MHz or PC3-6400
These speeds are relative to the theoretical bandwidths of each type of memory at its given clock speed when compared to another. A computer system can only use one type (DDR3 or DDR4) of memory. This should only be used as a comparison when the CPU is identical between the two computers. These are also the JDEC memory standards. Other memory speeds are available above these standard ratings. However, these speeds are generally reserved for computers that will be overclocked.
Dual-Channel and Triple-Channel
An additional item of note for computer memory is dual-channel and triple-channel configurations. Most desktop computers can offer improved memory bandwidth when the memory is installed in pairs or triples, called dual-channel when it is in pairs and triple-channel when in threes. If the memory is mixed, such as a 4 GB and 2 GB module or of different speeds, the dual-channel mode will not function, and the memory bandwidth will slow down somewhat.
Memory Expansion
Another consideration is the amount of memory the computer can support. Most desktop computers tend to have a total of four to six memory slots on the boards with modules installed in pairs. Smaller form factor computers typically only have two or three RAM slots. The way these slots are used can play a crucial role in how you can upgrade the memory in the future. For example, a computer may come with 8 GB of memory. With four memory slots, this memory amount can be installed with either two 4 GB memory modules or four 2 GB modules. If you are looking at future memory upgrades, it is better to purchase a computer using two 4 GB modules as there are available slots for upgrades without having to remove modules and RAM to increase the overall amount.
