In the title we summarize a question that surely we have all asked ourselves at some time. Whether we are going to buy a new laptop or desktop computer, or if we already have one and want to expand the amount of RAM available, it is very likely that we are wondering how much memory we need for our work and leisure.
Making an extra outlay to load our equipment with an excess of RAM that we are not going to take advantage of is not something pleasant, since we will always have a part of the RAM without squeezing and we could have allocated that part of the budget to enhance another part. Nor is it good to have a lack of RAM that slows down the execution of software or limits it.
If we are short of RAM or our equipment has become somewhat more outdated, the result will be slow software execution, limiting the amount of parallel work we can perform, etc. We will rely too much on virtual memory or Pagefile on Windows or SWAP on Unix / Linux systems. An obstacle to performance, especially if we do not have a solid state hard drive.
The opposite can also happen, having too much RAM and the performance is not as expected. In such a case, perhaps the limiting factor is in the CPU, GPU, etc. In that case, we should have allocated that budget destined to put more RAM modules to update or to acquire a somewhat superior CPU or graphics card.
These problems lead us to the next question
What does the RAM I need depend on?
This will depend so much on several variables, but mainly the key factor that will determine the amount of RAM you need is the type of software you want to run on your computer. Therefore, to answer the question properly, I first have to ask myself, what am I going to use my equipment for?
The answers can be very varied, from people who simply use the computer to surf the Internet, or office software, these cases being the ones that will require the least RAM (although it is true that certain browsers such as Chrome demand large amounts of RAM, especially if we have many tabs open at the same time), even playing multimedia with medium demand.
Other cases in which large amounts of RAM are required, such as video games, audio / video editing, 3D design and rendering, virtualization (especially if we use several virtual machines at the same time that each of them needs its own RAM space), simulations, etc.
The graphics card you use also influences the amount of memory you need to play without problems, as well as the speed of the hard disk (hence, first of all you detect all the bottlenecks that your pc can generate) and now we will see why what.
For example, a 3GB GTX 1060 typically uses higher system memory than a 6GB model, as when the former runs out of VRAM it uses system memory. If you run out of system memory, some game assets are moved to the local storage device, and depending on how fast that drive is, you may notice a drop in FPS.
Once you locate the niche or type of software that you are going to run to find out in the range of demand in which you are (low, medium, high), then you can take a look at the requirements or recommended requirements of said software that you are going to use. In this way, we will know the minimum amount that we should have. I say minimal, because you may be doing several things at the same time, therefore, having other programs that are consuming RAM in parallel. That should tell you that you should not have just enough RAM, but that I would add a little more than recommended in case this happens that I am talking about or a new version of the software comes out that demands a little more resources.
What CPU do I have?
It is another question that I should ask myself, since depending on this, we can move in some ranges of capacities or others. Especially if it is a multicore CPU, since depending on the number of cores we could assign certain GBs of RAM to each of them. Allocating an excess to each core will not have a particularly positive impact on performance, but it will cost more. Going short will limit performance and we don’t want that either. So, to give you an idea, you can assign about 2GB to each core, therefore, if you have an 8 cores, you could work with 16GB appropriately. In short, pay attention to the formula:
RAM = 2GB x Core No.
Remember that not by having an excess of RAM you will have more performance: it will depend on the workload and also on the clock speed and latency. In general, latency or access times (read / write) tend to decrease much more slowly than the clock speed of the microprocessor goes up. This leads us to the fact that we can run into bottlenecks.
How much RAM do I need?
Here comes the final question and answer. Well, if we have a 32-bit operating system and hardware, we already know that we will be limited to 4GB, but if it is a 64-bit system like all current ones, then it will be able to handle much more than that. And once we know our CPU and the software we need:
4 GB for light use: if your device is used only to browse, send or receive mail, run certain apps such as calculators, drawing, etc., and / or office software.
8-16GB for intensive use or gaming: if you use the equipment for CAD programs, video games, multimedia, etc. Keep in mind that although video games are among the software that demands the most resources, you only run one video game at a time.
24-32GB for professionals or enthusiasts: for professional work, video editing, 3D design, compilation, virtualization, simulation, scientific apps, etc.
Remember that if you work with virtual machines, you have to bear in mind that to these you will allocate several virtual cores of your CPU and GBs of RAM. But you probably want to double the amount per core that I explained earlier. That is to say, in a last generation microprocessor with 8 cores we could install 24GB to allocate a reasonable amount to virtual machines.
And that is because the case of virtualization is particular, since you are running the host operating system and on it we are using a hypervisor or virtualization software such as HyperV, VirtualBox, VMWare, Xen, etc., and on this other systems Guest operating with their apps in each one of them.
So if you are going to mount a new PC or want to upgrade the memory, the usual recommendation is 8GB, and 16GB for heavy users. For general use and games there is no advantage to using 16GB or more of RAM.