The role of RAM in a computer is to help you run a program and keep the data temporarily. As you might have also known, the higher a RAM capacity on a computer means the better the computer performance. However, most of the average users don’t know about RAM more detail when it comes to buying or upgrading a RAM.
Not all computers have the same type of RAM. There are several common questions from the average users asking about the types of RAMs, such as “what is the difference between DDR3 and DDR4”, what is the difference between DIMM and SO-DIMM”, and “what is the difference between DDR3-1600 and PC3-12800?”
Therefore, here we are going to discover more the basic points you need to know about RAM before upgrading your PC. Understanding the types of RAMs and RAM capacity and specifications are really necessary to avoid mistake while buying a RAM.
What is RAM?
RAM stands for Random Access Memory. The functions of RAM in a computer are to serve as a quick cache for your CPU and as a little data storage if comparing to HDD or SSD. It only stores temporary data from the operating system and the data of a software program that is running or being used.
Normally, the greater your computer RAM capacity means the faster you can access anything on your computer. However, RAM does not store data permanently, but when there is no incoming power such as when you turn off your computer, the stored data in RAM will be lost.
RAM also means SDRAM
SDRAM stands for Synchronous Dynamic Random Access Memory. It works to optimize the microprocessor of a computer, informing the user how fast the processor can perform its task. The speed unit of SDRAM uses Megahertz (MHz) instead of the nanosecond (ns). This makes the user compare the bus speed and RAM chip speed.
You can convert RAM clock speed to nanosecond by dividing it by 1 billion ns (or 1 second). For example, 83 MHz RAM will be equivalent to 12 ns. Mean 83 MHz RAM can do one task in 12 ns.
Initially, SDRAM has a speed of 66 MHz, and after the RAM development, the speed technology continues to grow up to 133 MHz. Finally, now we can find DDR-SDRAM on the market.
DIMM vs. SO-DIMM
Based on the size, there are two types of RAM, such as DIMM (Dual In-Line Memory Module) which we can find in desktop and server computer, and SO-DIMM (Small Outline DIMM), which we can find in laptops or smaller devices.
They both have the same technology, functions, and roles, but still, you have to put each of them where it should be. You cannot put the RAM DIMM into an SO-DIMM slot and vice versa. Each of them has a different shape. So, before buying a RAM either for a desktop PC or laptop, you need to know the shape of the RAM slot of your PC or laptop.
What is DDR?
When it comes to buying a RAM, you need to consider whether to buy a DDR, DDR2 or DDR3 RAM. DDR stands for Double Data Rate, which means two data transfers that occur per hour in a RAM. The newer types of RAMs have the same technology, but why does a RAM is labeled DDR, DDR2, DDR3, or DDR4?
Generally, the newest RAM products have the same size and shape but one couldn’t match to a certain type of motherboard. You cannot use a DDR3 RAM to a motherboard with DDR2 RAM slot or vice versa. It’s a striking difference of each of RAM generations which you can see from the pins.
DDR2 is the oldest generation of RAM. It has 240 pins and 200 pins for SO-DIMM. DDR3 was released in 2007, and currently becomes the standard of RAM capacity. But now, the technology of RAM DDR4 is becoming more common. DDR3 DIMM has the same pins as 240 DDR2, while a RAM DDR3 SO-DIMM has 204 pins.
RAM DDR4 is the latest generation of RAM technology. It uses 1.2V voltage with 260 pins. When you buy the latest computer product, surely it uses DDR4.
RAM Clock Speed, Transfers, and Bandwidth
You might be confused about the difference between DDR3-1600 and PC3-12800. So, here we are going to discover the difference between DDR3-1600 and PC3-12800. Such specification subjects to the RAM generation and transfer speed. After the number the DDR/PC, then it’s the generation of the RAM, such as DDR2 is PC2, DDR3 is PC3, and DDR4 is PC4.
The number of DDR refers to the number of transfers of its mega transfer (MT) per second. For example, a RAM DDR3-1600 works with a capability of 1600 MT/s. Theoretically, The number after the PC is the bandwidth in megabytes per second. For example, PC3-12800 works with 12.800MB/s.
So, you can also overclock RAM as well as CPU or GPU. There are some hardware companies selling overclocked RAM. However, you can do it yourself, but make sure the motherboard of you computer supports high clock speed.
When you are buying two RAMs for a computer, it’s recommended to choose two RAMs with the same clock speed. Though you can use two RAMs with different clock speeds, but the RAM performance on the computer tends to work at a low clock speed. It means, the RAM performance with a high clock speed will be in vain.
RAM Timing & Latency
You might ever see a short of numbers like a serial number on a RAM label, such as 9-10-9-27. It’s actually timing as the performance of a RAM in nanoseconds. The smaller numbers mean the faster the RAM performance on a computer.
As the first number (number 9) is the CAS latency or the number of clock cycles required to request data by the memory controller to the data pin.
Usually, a DDR3 RAM has a greater timing rate than DDR2, and DDR4 is greater than DDR3. It’s really bizarre when a smaller number get faster, but why DDR4 has a greater number? To explain, we can compare a DDR3 and DDR4 RAM. The lowest speed of DDR3 RAM is 553 MHz which means the clock cycle is 1/533000000 or 1.87 ns. With its 7 cycles CAS latency, the total latency would be 1.87 x 7 = 13.09 ns.
Meanwhile, the speed of DDR4 RAM is 800 MHz, which means the clock cycle is 1/800000000 or 1.25 ns. Even, if the CAS latency is 9 cycles, the total latency is 1.25 x 9 = 11.25 ns. So, a DDR4 RAM is faster than DDR3 RAM.
But most people take a look at the capacity and don’t pay attention to the clock speed or the latency time. You will get the benefit of a 16 GB DDR4-1600 than an 8 GB DDR4-2400. In most cases, the time and latency become the last points to consider.
Error Correcting Code (ECC) RAM is a special technique that aims to detect and repair corrupt data. Usually, EEC RAM is used on servers. However, not all motherboards and processors support EEC RAM, except for server computers that specifically require EEC RAM.
RAM Capacity Requirement to Adapt with the Recent Technology
Currently, there are smartphones which support 4GB of RAM capacity and the browser becomes a bit greedy with a lot of memory. So, today’s standard RAM capacity for a computer is a 4G RAM whether for Windows 7, Windows 8, or Windows 10.
If your computer performance is still slow when opening six Word documents or 40 Firefox tabs, or even you often run a virtual machine like VirtualBox, probably you should upgrade your RAM capacity to 8GB. While a 16GB RAM is needed if you are a gamer or doing heavy activities such as video rendering. What about 32GB RAM? For now, 16GB is more than enough, but if you a 32GB RAM is much better.