Modern CPUs, RAMs, and HDDs

Modern CPUs, RAM and Hard Drives

In this article, we are going to explore three fundamental hardware components that vary from computer to computer— CPUs, RAM and Hard Drives. We are going to come from two angles to give you the full picture. First, we’ll talk about what each component is and how it works. After that, we’ll talk about the modern history of the components and some of the common names you will see when you are out there shopping.


The CPU is the Central Processing Unit of a computer. This is the most fundamental component of any system: it is the brains, it is the controller. How does it work? A CPU is a deterministic machine. This means that it receives inputs from the external world and responds in a predictable way. If you know the set of inputs that are going into a CPU, theoretically you would be able to predict how it will respond every single time. Specifically when it comes to the CPU, the inputs are called “instructions.” Instructions to the CPU are the basis of computer operation and are very simple, such as add number X and number Y and save the result. The idea of a computer program is a long list of these instructions and “running” a program means sending the instructions through the CPU. The CPU is built out of millions of electronic components called transistors. To understand more about the design of a CPU, read up on digital logic here.

When you are shopping for a computer, the CPU (also known as the processor) is one of the key parts that will tell you how fast your computer is.  The two biggest processor manufacturers today are Intel and AMD. Intel processors are currently the best on the market, but there are some cases in which an AMD processor can be more economical and efficient. Intel has been making processors for decades and has had dozens of product lines that you may or may not have heard of before, like the Pentium, the Xeon and the Celeron. What’s important to remember is, the newest processors are the most powerful, and each processor name may have many versions associated with it.

Core 2 duo

Example Core 2 Duo Intel Processor

Intel’s current top-of-the-line processors are the i-series, which come in the i3, i5 and i7 versions. Intel has been making the i-series for over five years now. You may also encounter the Intel 2 Core Duo, which is an older but still powerful processor.

The way it works is, Intel will come out with a new processor and give it a name, like the Intel Core i7 processor. While the i7 came out in 2008, it has been constantly improved upon with new versions over the years. While the newer versions are still called i7 processors, they come with different numbers associated with them, so the i7-7500U is actually a 7th generation processor (due to the 7 in 7500). Just remember that there are multiple versions of each processor even if they have the same name. Same idea as iPhone 4, 5, 5S and 6.

So, what distinguishes one processor from another? Some of the key performance indicators are

1) The clock cycle rate which you’ll usually see look something like: 1.3GHz. A clock cycle is like a computer’s heartbeat of electrical impulse, giga means billion, so 1.3 GHz is 1.3 billion pulses per second. Theoretically, a higher cycle rate means a faster processor, but this is not necessarily the case, as we’ll see below.

2) The number of cores: each of these intel CPUs actually come with multiple processors put together on one chip! What this means is that processors can potentially read twice as many instructions at one time. This is one of the reasons a faster clock cycle rate does not mean a definitely faster processor— if another processor has multiple cores at a slower rate, it may be faster overall.

3) Special features like turbo boost and hyper threading abilities. The intel i-series processors have the ability to turbo boost— which means increase their clock cycle rate if possible — and to hyper thread— which means running twice as many instructions through each processor, simulating even more cores!

Overall, you will hear a lot of different opinions on which processors are the fastest, but the main idea is maximizing the number of instructions being read and this is usually measured in the cycle rate, number of cores and special features.

Here is a table distinguishing the i-series and core 2 processors:


Number of cores

Clock Rate

Core 2 1, 2 or 4 1.06-3.3 Ghz

Core i3

2, all hyperthreading

1.2-3.7 GHz

Core i5

4, 2 hyperthreading

1.06-3.6 GHz

Core i7

4, all hyperthreading

1.6-4.4 GHz

The i7 processor is the best, followed by the i5, the i3 and the core 2. Core 2 and i3 processors are best for a comfortable computer that can surf the web, send emails and do some simple word processing. The i5 is an excellent standard for speedy enterprise work and the i7 is the best– good for gaming and serious computational work.

As for a quick overview of AMD processors, they are generally cheaper and have a worse price-performance ratio than Intel’s processors. However, cheaper quad-core processors like the A6-5400K may be more effective for parallel computing, since you can get more cores for less. Overall, AMD overclocks (turbo boost) for cheaper and has higher power consumption per chip than Intel. This high power consumption nearly pushes AMD out of the laptop market.

The main AMD processors to look out for are the FX-series chips (8 and 9000) for desktops and the A-series for laptops (A12/10/9/6, E2). If you can’t afford a the i5 it may be good to go for an AMD processor.


There are two types of memory in a computer– RAM and disk space. Disk space is permanent memory that saves all of your files and preferences every time you turn your computer on and off. RAM is temporary memory that holds all the current programs you are using and the data you are working on. Having too little RAM can make your computer a lot slower so it is one of the key aspects of computer performance.

The two main types of RAM are DRAM and SRAM. DRAM stands for dynamic random access memory and SRAM stands for static access memory. Imagine that RAM is a large grid of discrete data chunks. Random access memory refers to the way in which the computer is able to take any piece of data from any place in the grid, instantaneously. Dynamic RAM uses the electronic components capacitors and transistors to store data. Because capacitors store charge but dissipate over time, DRAM requires a memory controller to recharge the capacitors and refresh the state. Static RAM is designed with 4-6 transistors in place of the capacitors and, therefore, does not require a refresh. SRAM is significantly faster, but because there are more electronic components, it takes up more space and is more costly per amount of memory.

For this reason, the RAM that is more frequently used to speed up your computer performance is DRAM (SRAM is more used for the processor’s cache). The main types of DRAM on the market today are DDR3– Double data rate type three SDRAM– and DDR4. DDR3 is the current industry standard and has been in use since 2007. It is twice as fast as its predecessor, DDR2. DDR4 is the successor to DDR3 and was released in 2014, but it is not backwards compatible. Currently, there is enough demand for DDR3 and little demand for DDR4, so DDR3 is still the most prevalent RAM used.


Animations of DDR, DDR2 and DDR3 RAM.  The big difference is the data transfer rate and power consumption by each.  

Size & Speed

Because RAM is the memory where current programs are run and store data, RAM that is too small will allow only a finite number of programs and data space available at a time without needing to intermittently swap data with the permanent disk memory. Retrieving information from disk is a very slow process, so by increasing the size of RAM, the less likely it is you’ll need waste time swapping data.

We know that RAM affects the speed of your computer, but how much RAM do you really need? Most computers today will come with at least 2GB of RAM. Technically, 1GB RAM is the minimum required for Windows 10 (32-bit version), but this will be a pretty slow and ill-advised experience. 2GB should suffice for the casual user, but will not really be enough to run multiple programs or run any resource-intensive applications. With 4GB RAM things start getting a lot faster. You’ll be running multiple applications at once smoothly and shouldn’t have any problems with basic operation. 8GB RAM is the performance standard. You will need a 64-bit operating system to fully utilize the 8GB memory space effectively. At 16GB, you may start to stop seeing the effects unless you are using really resource intensive applications like CAD, 4K video and image processing or running large computational programs. Over 16GB is relatively unlimited and would only be useful if you are doing something really serious.


The other type of memory in a computer system is long-term storage, also known as disk memory. Traditionally, disk memory came in the form of a Hard Drive Disk (HDD). HDDs consist of a spinning circular metal plate with millions of discrete magnetic bits that are accessible via a magnetic read-write head. As the plate spins in circles at up to 10 meters per second, the read-write head moves in and out radially in order to access physical areas where information is stored. This means that data on a HDD is usually contiguously stored.

hard drive

A conceptual HDD

In contrast, today Solid State Drives (SSD) are a newer, faster storage setup that stores data permanently using flash memory, a transistor-based setup (although some manufacturers do use DRAM as well!). SSDs are much faster for a number of reasons— they don’t have any physically moving pieces unlike spinning HDDs and they can store data in various locations since they do not have a static read-write head and flash memory is fast. SSDs are also much quieter and don’t break as easily when dropped since they don’t have a spinning disk inside. HDDs tend to come in standard 2.5 and 3.5 inch containers, however these restrictions are less necessary for SSDs as they are much thinner and can be much smaller.

Comparing HDDs and SSDs at price points, HDDs are much cheaper for the amount of memory they store. An internal 1TB hard drive can average $50-75 for an HDD but the same size SSD could be $200-300.

Another disk storage distinction is the internal vs. external hard drives. Internal hard drives come with your computer and may potentially be replaced, but not always easily. This also may void the warranty if the manufacturer of your computer stipulates that you mustn’t open the computer. External hard drives are usually connected to your computer via USB or firewire cables and can be an affordable way to increase your computer storage. You may also find it more convenient to have your memory be easily transportable. However, external hard drives tend to be slower since they require communication over USB or firewire, whereas internal hard drives communicate directly through the motherboard. Today’s external HDDs are pretty affordable— 3-5TB for $150 or less.

In a recent study by Backblaze, HDDs were ranked by their annual failure rate. Apparently, 80% of drives last for up to four years. Some of the highest ranked hard drives were Hitachi, Western Digital and Seagate. Toshiba and Samsung also make hard drives.