There's nothing nerdier or more mundane than understanding the difference between DDR4 and DDR5 RAM — and yet it's exactly the thing you should insist on knowing when choosing a new computer.
Why?
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RAM serves as a bridge between the data stored on your hard drive and the data on which the processor is actively performing calculations.
When you're writing a document in Word, the operating system, the Word application, and the document you're working on are all stored in RAM. When you save, the data is written to the hard drive and stored there.
RAM is a performance bottleneck because the processor operates at a far higher rate than RAM can supply data. This means the processor has to wait for RAM to deliver new information.
RAM speed is measured in MHz — the higher the clock rate, the faster it can transfer data.
For many years, the standard RAM type was DDR4, typically running at speeds between 2666MHz and 3200MHz.
The newer DDR5 RAM modules start at 4800MHz on entry-level models and exceed 7000MHz on high-end ones.
In practice, this translates into a vastly better user experience compared to DDR4 — so the next time you're buying a computer, make sure it comes equipped with DDR5.
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For the advanced reader 😉:
Does doubling RAM speed mean doubling performance?
The answer is no.
Despite a significant performance improvement, simply doubling the clock rate will not double performance.
The reason is a value called CL (CAS Latency), which measures the response time before RAM returns new data. The higher the CL value, the longer it takes the memory to respond to new data requests from the processor.
As clock speed increases, it becomes harder to maintain a low CL — meaning that some of the performance gain is offset by the increased response time.
Higher clock speeds also generate more heat, which is why high-speed memory modules are typically fitted with a metal heatspreader to dissipate heat.
Higher clock speeds come at a cost to system stability as well, so the default setting will generally not exceed 5600MHz. Additional speed is achieved by adjusting BIOS settings or installing an XMP profile — a topic for another time.
In the photo:
A pair of DDR5 desktop RAM modules, featuring RGB lighting, a metal heatspreader to prevent overheating, and a maximum speed of 6000MHz.
Photo credit: White Tiger