Content of the material
- Does Memory RAM Have to Match?
- Understanding RAM Specifications
- 1. Memory Form Factor
- 2. Memory Type Or Generation
- 3. Memory Size
- 4. Memory Speed
- 5. Memory Latency
- 6. Memory Voltage
- 7. Memory Brand
- Mixing RAM Brands: Does RAM Type Count?
- Can You Mix Different RAM Speeds?
- Can You Mix RAM Sticks of Different Sizes?
- Planning Your Memory Configuration
- Recent Posts
Does Memory RAM Have to Match?
RAM sizes can be mixed, but it’s often not recommended as it can decrease computer performance. It’s recommended to match RAM sticks by the same manufacturer, with the same size and frequency.
RAM (random access memory) is a necessary computer and smartphone component. The job of RAM is to remember computations for a limited amount of time, so that the computer processor doesn’t need to redo the computations every time.
RAM sticks by different manufacturers are usually made out of differing components. RAM from the same vendor can be made out of different components over time.
This is often why RAM sticks are sold in kits of 2x4GB or 2x8GB, to ensure that they are identical and compatible with each other.
Some motherboards are very sensitive to this as it has to manage all the RAM using the same specifications of voltage and speed. This makes it more difficult to manage different sizes or makes of RAM.
Different sizes of RAM can be used together, but for them to perform optimally, the same voltage and controllers should work well with each other, and the motherboard. Usually for this reason, it’s recommended to use the same model in all slots.
The issue you’ll most likely encounter with different RAM sticks is an incompatibility between the two RAM sticks, incompatibility with the motherboard, or a limitation in your motherboard’s design.
Things to consider when buying RAM outside of kits:
- Speed of memory. A stick at 1600mhz speed and another at 1333mhz speed will cause the 1600mhz stick to be slowed down to match the slowest module.
- Size of memory. An 8GB stick will need 8GB or higher or it won’t work.
- Latency of memory. Latency of CAS 9 and CAS 11 will mean the computer runs at CAS 11, which is slower.
Dual channel mode can run different size RAM sticks, but it won’t be optimal. For example, a new 8GB stick and an existing 4GB stick will perform as two 4GB sticks running side by side, while the remaining 4GB of the new 8GB stick will run in single channel mode. It’s not as fast as using two sticks of the same size, but it will be faster than before.
Using two same sizes of RAM sticks can yield up to 5% extra speed in dual channel mode without needing extra hardware.
A 5% boost is minimal, but 5% more speed for free is a nice benefit, which is why users are recommended to use identical RAM sticks.
If there are more than 2 slots, 3 sticks can be used as well. One pair will run in dual channel mode, while the last stick will be in single channel mode.
For a guaranteed run, the exact same model and manufacturer of RAM stick should be used. Latency and voltage should also be the same for the best speed compatibility.
Understanding RAM Specifications
To fully understand the answer to the big question about mixing RAMs, you need to know what specifications and features define a RAM.
If you’re already a pro in this area, skip this section and go straight to the answer.
1. Memory Form Factor
RAM modules are available in two primary and standard form factors:
- Dual In-Line Memory Module or DIMM: The DIMM is the RAM form factor used for desktop computers, and it refers to the physical size of the RAM stick, which is bigger for desktops. The standard length is 133.35 mm for DIMMs.
- Small Outline DIMM or SO-DIMM: SO-DIMM RAM modules are for laptops and compact computers in general. They’re almost half as small as DIMMs, at just 67.6 mm in length.
2. Memory Type Or Generation
As technology has evolved over the years, RAM sticks have also improved and gained more enhanced features and capabilities.
There are five main generations for the DDR SDRAMs (Double Data Rate Synchronous Dynamic RAM) that are commonly in use today:
- 2000 release: DDR1 SDRAM
- 2003 release: DDR2 SDRAM
- 2007 release: DDR3 SDRAM
- 2014 release: DDR4 SDRAM
- 2020 release: DDR5 SDRAM
There’s no backward or forward compatibility between these RAM generations, and you can’t fit one into a slot made for the other since they use a different number of pins.
3. Memory Size
RAM sizes refer to the capacity of each RAM stick and how much information it can store.
RAM modules come in different sizes, varying from 2GB to 32GB.
For instance, you can get two 4GB RAM sticks, so your computer has a total of 8 GB memory space.
4. Memory Speed
RAM speed or frequency is the number of cycles a RAM stick can perform every second.
The higher the RAM frequency, the more data your RAM can read and store, and the smoother your system will work.
RAM frequency is measured in megahertz (MHz), million cycles per second.
For example, if you see the number 3600MHz next to a RAM’s name, you’ll know that it can perform 3.6 billion cycles per second.
That means the RAM stick can transfer that many bits in one second!
5. Memory Latency
Latency is the amount of time it takes a memory module to respond to a call or command your system gives by accessing a specific set of data in one of its columns.
You’ll see the letters “CL” next to a number in a RAM’s specifications, indicating its latency.
For instance, a CL16 RAM stick will take 16 cycles to respond to a command.
The lower the latency, the faster your RAM will be.
6. Memory Voltage
The power that the DRAM modules consume is referred to as their voltage.
Different RAM types and models have different voltages ranging from 1 V to 1.4 V.
You can make your RAM run at different voltages to adjust performance and stability, but it’s not recommended to overclock it more than 1.5 V.
7. Memory Brand
Different manufacturers or assemblers are making RAM sticks and putting them up for purchase, and each has a different brand name.
It’s a known fact that two different manufacturers can make the same RAM sticks and sell them in slightly different packaging.
However, you can never be sure since they never publicize all RAM specs or retailers.
You could find two RAM modules with the same type, size, frequency, latency, and voltage, but the memory and controller chips could end up being different.
Mixing RAM Brands: Does RAM Type Count?
The RAM types available are the DDR1, DDR2, DDR3, DDR4, and the DDR5, which is the latest release. DDR also means Double Data Rate.
Each generation denotes the RAM types, and DDR4 is actually one step higher than DDR3. And yes, RAM type matters a great deal when it comes to combining RAM brands. If the RAM doesn’t fit into the motherboard slot, then it’s a big waste of time and energy.
So, you can’t and shouldn’t try fitting a DDR2 into a DDR3 slot on your PC’s motherboard. It doesn’t matter if they are of the same brand or not. If a RAM kit doesn’t fit into your PC or computer’s motherboard, how then will it work or deliver optimal performance?
Can You Mix Different RAM Speeds?
It’s not uncommon to mix RAM kits with different speeds, but you should know that a chain can only be as strong as its weakest link.
When you combine two RAM sticks with different frequencies, you should expect your motherboard and the memory controller to underclock the faster RAM, configuring the kits to run at the speed of the slowest module.
They’ll likely work just fine, and you won’t notice any issues, but you’ll feel the lack of performance when you’re doing intensive tasks like gaming.
You might be able to overclock the weaker RAM sticks, but you’ll risk overheating and lagging issues.
The above scenario is for when you’re lucky enough to get the RAMs working.
You probably will run into errors with such a setup, like BSOD errors and frequent crashes.
The risk will be higher if you pair older RAM models with new ones.
Overall, mixing and matching different RAM sizes, speeds, and latencies generally will not cause any serious issues such as crashing or freezing, but the user may experience lower performance on the system. Besides that, there may be incompatibility between the different RAM sticks with the motherboard.
No related posts.
Can You Mix RAM Sticks of Different Sizes?
When upgrading RAM, it’s recommended that you upgrade in pairs of equal size, frequency, and manufacturer. Also, ensure that you verify your PC model to ensure that the RAM is compatible with your system using the manufacturer’s website or user manual of the motherboard.
If you install one single 16GB DDR4-3200MHz module in your system, it will only run at 1600MHz, known as (single-data rate). Also, if you install two or more RAM modules, such as one 16GB DDR4-3200 and one 8GB DDR4-3200, the dual-channel mode will be disabled, which can seriously reduce your PC’s performance.
On Intel motherboards, that support Intel Flex mode, however, the extra portion of the larger RAM module will run in single-channel mode, and the first chunk of matching 8GB on the mis-sized modules will run in dual channel mode. AMD motherboards are more sensitive to mismatched RAM sizes and usually throw instability issues.
Another issue with mixing RAM is latency. Latency is the number of clock cycles (measured in nanoseconds) it takes to access data in one of the RAM modules columns.
If you install an 8GB Module of RAM with an 18 CAS latency and one 8GB module with a 16 latency, the modules will operate at the slowest CAS latency. Meaning both modules installed will run at 18 CAS latency.
Although these methods have been tested, it serves to mention that there are reports of people receiving a BSOD (Blue Screen Of Death) on occasion due to incompatible RAM sizes in their PCs. Intel offers FlexMode that allows greater flexibility when installing different RAM varieties.
To enable a PC without Intel FlexMode, such as an AMD-powered machine to get the most out of your RAM, install two identical RAM modules (sold as kits in pairs) such as (2) 16 DDR-3200 into your motherboard in the correct slots.
Look to your motherboard’s manual or manufacturer’s website for more information.
Typically, the arrangement is properly drawn in the motherboard’s user guide or manual, and also found on the respective manufacturer’s website. This arrangement shows the sequence of filling multiple RAM slots, for the proper dual-channel mode, and is especially critical for boards with more than 2 RAM slots.
Planning Your Memory Configuration
Depending on the manufacturer of your CPU, the optimal specifications will differ.
If you are wondering how much memory you should purchase, it will depend on the workload you wish to accommodate.
For video editing, for example, 32 to 64 GB of RAM is recommended, while for gaming 16 GB will suffice.
For AMD processors, the best RAM speed to aim for will be double the internal frequency of the Infinity Fabric – also known as FCLK or Fclock. This double data rate will assure a level of synchronicity between your CPU and RAM that will achieve optimal performance.
For Zen 2 and Zen 3 CPUs, the FCLK is 1,800 MHz; so a 3,600 MHz CL 16 RAM kit is a future-proof speed metric.
This kit speed has proven to provide better performance than a 3,200 MHz CL 14 kit, despite having a larger absolute latency metric (8.89 ns vs 8.75 ns).
Do note that the FCLK value can be overclocked; so if your workload requires faster frequencies, you can purchase kits that have a double-data-rate frequency of the overclocked FCLK value.
For a full breakdown of the best memory for AMD CPUs, check our relevant article.
Also, it must be noted that Samsung’s B-Die has been proven to be the best RAM-die for AMD processors.
Purchasing RAM sticks for an Intel CPU is also quite simple, as they have been benchmarked and factory-tested at a specific RAM kit speed: 3,200 MHz CL 14.
These specifications are in accordance with Intel’s internal testing, so it is safe to label this speed as the sweet spot for Intel CPUs.