What RAM Is Compatible With My PC Motherboard

Have you finally realized you need more RAM? Or did you figure out your current RAM sticks are faulty after a diagnosis?

Or you’re a new PC builder, and choosing the correct RAM means you will have to decide on the capacity, type, price, timing specifications, and profile height. I’m here to help you navigate the not-so-difficult path to finding the perfect RAM modules for your PC.

Important Things To Consider When Buying a RAM

  • What type of RAM do I need (DDR2, DDR3, or DDR4)?
  • How much RAM do I need?
  • What is the maximum supported RAM frequency by my motherboard?
  • What is the maximum RAM capacity supported by my motherboard?
  • How much clearance is available for heatsinks on the RAM in my Casing?
  • What RAM is Compatible With My Motherboard?

    RAM Motherboard Compatibility

    The most accepted and easy method in choosing the appropriate RAM for your computer is to look inside your motherboard’s manufacturer’s manual. This user manual lists all of the specifications of memory that it can support.

    If you don’t have this manual, see the motherboard manufacturer’s website for this information. Typically, most of the vendors have a list called Qualified Vendor List (QVL) of RAM modules with timings, frequencies, and model numbers to exactly know what RAM sticks to search for your computer.

    For laptops, manufacturers offer a user manual or service manual to the end-user. The user manual lists specifications for the replacement of all parts on the laptop. Again, also see the manufacturer’s website if you do not have this information.

    What if I Need More Ram for My Old PC?

    RAM for my older PC

    Adding RAM to a PC is easily one of the best ways to increase your system’s performance. RAM can increase speed, productivity and boost your PC, old or new.

    However, memory compatibility issues due to two or more different RAM sticks can cause various issues like BSOD, instability, etc. So, in most use cases, I suggest you buy a new dual-channel DDRx kit, having 2 sticks of RAM that are guaranteed to be identical.

    The older RAM sticks can be discarded, since, even two slow sticks will degrade the newer faster RAM sticks’ performance, assuming you have 4 RAM slots to use both kits at the same time. (Kit meaning 2 sticks of identical RAM modules)

    You can also go the hard way and find a module (or two) that matches your current RAM sticks’ timings, capacity, clock-speed sufficiently closely. Mismatching different timings and specifications will firstly result in performance degradation to the slowest RAM stick and can cause instability issues.

    The other downside of upgrading older PC’s RAM is the cost. If you wanted to upgrade to 8GB more RAM, you will pay around $179 for DDR2. You would only pay around $27 for DDR3. If you were upgrading to DDR4, it would cost about $60.

    As you can see, there is a steep price difference between older RAM and DDR3 and DDR4. If your system is running well otherwise and you don’t want to invest in all new components, go get cheaper DDR3 or DDR4, it might be a less expensive choice overall.

    So, even though a RAM upgrade feels small, the costs of the older generation are usually very inflated due to supply shortages. After a product reaches EOL, the only products in circulation are either remaining supply or refurbished parts from the Used PC market.

    Please take this into consideration, if your PC only supports 2 generations older DDR memory than the current market technology. I would not recommend you a RAM upgrade of a DDR1 or DDR2 memory even for small prices, since, there is no guarantee of a working fresh module.

    Insertion Order and Single Replacements Can Affect RAM Compatibility 

    One thing to remember when you install the RAM sticks is that when you install more than 2 RAM sticks, you’ll need to know which order to insert each RAM stick. This is part of the compatibility factor in that if you install them in the wrong order, they won’t function optimally.

    The specific slots that will need to be filled in sequential order, for more than 2 sticks of RAM is usually properly depicted in your motherboard’s user manual (and sometimes even on the motherboard itself).

    Basically, this is all you should need to find which RAM modules available are compatible with your computer and install them correctly on your PC. However, if you want to know more about the technicalities of RAM modules, and make an even smarter decision, read on further below.

    What Generation of RAM Do I Need?

    RAM Generations

    Today, many machines still use DDR3, which has been standard in PCs since 2007 and is still widely sold. RAM form factors differ with each generation.

    Each generation change such as “DDR3 to DDR4“, changes its form factor so it is not possible to accidentally insert the incorrect RAM into the slot.

    One important reason for this is that electronic specifications change with each generation, such as DDR4’s lower voltages compared to DDR3’s. The voltage variations could cause serious damage to the RAM or other peripherals.

    The advantage that DDR4 has over DDR3 is that they are more energy-efficient since DDR4 RAM runs at a lower 1.2V compared to DDR3’s 1.5V or 1.35V. This reduced power consumption and increased transfer rate make DDR4 more desirable.

    Identifying Using Stickers on the RAM Sticks

    There are several ways to identify the differences between DDR3 and DDR4. The easiest of them is the sticker that is on the RAM itself. If there is a sticker on the RAM, it should provide information about your installed type.

    If the sticker is not present or does not provide this information and you cannot install the programs mentioned above. Look at the voltage of the RAM using your motherboard BIOS. The table below shows the voltage comparison of all RAM form factors from SDRAM to the cutting-edge new DDR5.

    DDR SDRAM Standard
    Internal Rate(MHz)
    Bus Clock(MHz)
    Release Year
    Data Rate(MT/s)
    Transfer Rate(MB/s)

    Identifying Using Third Party Apps

    There are quite a few third party apps easily available on the web for displaying the component specifications of your computer. For example, AIDA64/ CPUZ / HWinfo all work fine for checking what RAM does your PC has currently, and more. Most motherboard BIOS also shows limited information on this.


    By using Speccy, we can see the memory type as DDR3. We can see there is a total of 16GB of Dual-Channel RAM.

    The speed or frequency of the RAM is 797.8MHz. Since this computer uses Dual-Channel RAM, the speed is doubled, making the total speed around 1600MHz.

    We can also see how many memory slots are available on the motherboard and your memory usage.

    How Is Laptop RAM Different From Desktop RAM?

    Removing SODIMM RAM

    The small form factor RAM or SO-DIMM (Small Outline – Dual In-Line Memory Module) RAM is the one used in laptops. The difference in SO-DIMM laptop RAM is its physical size.  SO-DIMM is much smaller at 2 ½ to 3 inches in length. 

    Desktop RAM or DIMM (Dual Inline Memory Module) DDR3 and DDR4 are both approximately 5 ¼ inches. The other difference is that Laptop DDR4 (SO-DIMM) has 260 pins where Desktop DDR4 (DIMMs) has 288 pins.

    Laptop DDR3 (SO-DIMM) has 204 pins whereas the desktop DDR3 has 240 pins.  Other variations of SO-DIMM and DDR can be seen in the chart below.

    Memory Type
    SDR Memory Type
    DIMM 168 pins
    SO-DIMM 100/144 pins
    DDR Memory Type
    DIMM 184 pins
    SO-DIMM 200 pin
    DDR2 Memory Type
    DIMM 240 pins
    SO-DIMM 200 pin
    DDR3 Memory Type
    DIMM 240 pins
    SO-DIMM 204 pin
    DDR4 Memory Type
    DIMM 288 pins
    SO-DIMM 260 pin

    What Do RAM Clock Speeds and RAM Timings Mean?

    Now we are going to start getting a little bit more technical.  Each RAM module has two memory timing specifications that you want to look for.  One spec is the frequency or the number of times something happens over a set period.

     This is the bus speed of a DDR RAM module. You usually see this depicted as 2133 MHz, 2666MHz, 3000MHz, etc. in dual channel DDR3, DDR4 modules’ descriptions.

    The second spec you want to look at is latency, which is how long it takes to catch up.  These two specifications are important if you are looking to get the most out of your RAM purchase.

    Clock Speed and Timings

    In the image above, you will see a series of numbers (CL 11-11-1-28) that define the latency of your RAM module. The series of numbers start with CAS (Column Access Strobe) Latency or CL usually.

    CAS is the time that it takes for your RAM to start responding to a request. This number depends on the number of clock cycles which is the frequency of 1600 MHz for this example.  

    The second number contains the tRCD (the Row to Column Delay). These numbers indicate the time it takes to search each row to find the column of the data it is searching for and stored.

    The third number is the tRP (the Row Precharge). The Row Precharge defines the necessary time it takes for the RAM to open a new row.

    The fourth and final number is tRAS (the Row Active Time). The Row Active Time is the minimum number of clock cycles that a row must stay open to ensure that information is read or written correctly.

    This number should be greater or equal to the total of all other numbers listed above (CAS + tRCD + tRP = tRAS).

    Knowing all the above, aim for the ideal combination of:

  • lowest timings, especially the CL (first number of the sequence)
  • highest frequency (rated stock speed of the module)
  • lowest voltage
  • lowest price
  • compatiblity with your motherboard (Qualified Vendor List of each motherboard or QVL)
  • How Much RAM Capacity Do I Need?

    Capacity of RAM

    If your system doesn’t have enough memory, it will attempt to use your hard disk drive to help reduce the workload. This process utilizes Windows virtual memory (pagefile) or paging. Every time you open applications that the RAM on your machine can’t handle, it transfers the program to the pagefile.

    The bad thing about paging is that it can overwork the hard drive. When your system doesn’t have enough RAM, your hard drive will be working overtime trying to keep up with all of the processes.

    Not only is this process much slower than a normal RAM process, but it can also cause memory allocation errors and hardware failures due to the increased read, write, and re-write on the hard disk drive.

    Crucial recommends “4GB of RAM for casual internet browsing and email, at least 8GB for those using spreadsheets and flash games, and at least 32GB for gamers.”

    However, in our experience, 8GB is the minimum, and we recommend a perfect 16GB of RAM for gaming/media consumption/streaming, and 32GB for video editing, content creation and content manipulation.

    4GB of RAM barely even makes it for basic browsing in the Windows environment, circa 2021. Linux is different and could work with this much RAM, not smoothly but better than Windows.

    Another thing to consider is your processor’s architecture. If you are using a 32bit (x86) OS, it will not utilize more than 4GB of RAM. However, if you have a 64bit Operating System (x64), you can utilize much more depending on your maximum motherboard specifications.

    I should also mention that some CPU chip makers, such as Intel, limit the RAM frequencies based on the type of processor.

    Finally, Choosing My Ideal RAM…

    Choosing my ideal RAM

    With so many manufactures of RAM out there, you may be wondering which one you should purchase. The rule of thumb is always to choose a well-known, trusted supplier for any PC component.

    Many Memory vendors exist and provide excellent quality products. A lot has to do with personal preference, availability, aesthetic value, price, and warranty offers.

    Some very prominent RAM vendors are Crucial, Corsair, G.Skill, Kingston, Transcend, ADATA, Apacer, etc. It is very important to do your homework, utilize all of the information in this guide to make a sound decision on a quality product that will provide you with the speed and performance you require.

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