There's nothing nerdier or more mundane than understanding the difference between DDR4 and DDR5 RAM — and yet it's exactly the detail you should insist on 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 actively performs calculations.
When you're writing a file 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 far faster than RAM can supply data to it — meaning the processor must wait for RAM to deliver new information.
RAM speed is measured in MHz: the higher the clock rate, the faster data can be transferred.
For many years, the standard was DDR4 RAM, typically running at speeds between 2666MHz and 3200MHz.
Newer DDR5 RAM modules start at 4800MHz in entry-level models and exceed 7000MHz in 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 the memory takes to respond to new data requests from the processor.
As clock speeds rise, maintaining a low CL becomes increasingly difficult — meaning that some of the performance gain is offset by the increased latency.
Higher clock speeds also generate more heat, which is why high-speed memory modules are typically fitted with a metal heatspreader to dissipate heat.
Stability is another cost of higher clock speeds, which is why the default setting generally won't exceed 5600MHz — with additional speed achieved by tuning 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