RAM

Computer memory, also known as RAM is another important component of every computer. For machine learning applications, it’s critical, especially if users are working with large datasets. There are several manufacturers of RAM and even more, retailers that sell it. Some popular brands include the following:

The current standard is DDR4 which supports 3.2 Gbps bandwidth compared to 1.866 Gbps for DDR3. That’s more than 50% better data transfer rates than the previous generation. DDR5 is already out but it will take some time before it becomes the standard. Motherboards are not backward compatible, as such, there are no mixing different generations of memory modules. DDR4 also consumes less energy than DDR3, the current standard is 1.2V. DDR5 consumes 1.1V. Lastly, DDR4 supports 64GB DIMM, which is 4x its predecessor. Here are the specs for DDR4.

Features	DDR3	DDR4	DDR5
Bandwidth	1.86 Gbps	3.2 Gbps	4.8 Gbps
Performance: MHz/MTS	800 to 2133 MHz	1600 to 3200 MHz	2400 to 3600 MHz
Max Capacity for DIMM	16GB	64GB	256GB
# of Pins	240	288	288
Voltage	1.5V	1.2V	1.1V

Compatibility

When it comes to building your own system, there is always a concern about the compatibility of DIMM modules. Install one pair of RAM modules today and the same size pair from the same manufacturer in the future when it’s time to upgrade, there is a chance all four might not work together. The issue is compounded when different size modules are used, like a pair of 16GB and 32GB, or mixing different manufacturers like Kingston and Corsair together.

Here is a set of best practices to reduce RAM compatibility issues.

Ideal Scenario: If possible, buy all RAM modules that you need at once. Thus, if a server motherboard comes with 8 DIMM slots and it is decided that 512MB is needed, buy and install 8x64GB modules at once. When sticks or RAN are sold together, it means they have been tested together and should work together. However, there is no 100% guarantee it will work with the motherboard of choice but the odds of the RAM and motherboard playing nice together are improved.

Second Best Scenario: If there is a lack of budget, then buy pairs today and in the future from the same manufacturer. For example, buy 4x64GB sticks from Corsair today, then buy the same models in the future. For example, if a server motherboard comes with 8 DIMM slots for memory, buy 4x64MB (or any other speed) today and 4x64GB in the future from the same manufacturer.