Why Can't We Use SSDs as RAM?
Asked by
CuriousCat1234
I've been doing some basic research and here's my thought process: An 8GB stick of DDR5 RAM can run up to 8000MBps, while a Gen 4 or 5 SSD can reach speeds of about 10,000MBps. I realize the speed measurements differ, but essentially, both components are solid state drives designed for different purposes. My main question is, what's stopping us from using an SSD chip as RAM? Is it possible? I'd love an explanation of where my thinking might be flawed or if there are solid reasons against it.
Answers
Latency is a crucial factor here. RAM is much faster than SSDs in terms of latency—it's dozens to thousands of times quicker. When your CPU needs data, it requires it almost instantly to prevent delays. While your speed comparisons seem valid, DDR5 actually transfers data at about 32 GB/s, significantly higher than the 8000MBps you mentioned. SSDs just can't keep up in terms of response time.
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There’s a significant difference between SSDs and RAM. One key point is that RAM is volatile and loses its data when the power is off, while SSDs retain data. Additionally, DRAM can handle many more writes than NAND flash used in SSDs, which wears out faster with frequent writes. So, fundamentally, they're built for different tasks, and you can't just swap them out.
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Using SSDs as RAM is technically feasible if you adjust system settings like the page file size, allowing the SSD to help supplement RAM. However, this can be really slow and is typically not a great idea as a permanent solution. Plus, this could potentially wear out the SSD faster, so most people just stick to using actual RAM.
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MemoryMaster42: Totally agree! While it’s clever to repurpose at times, it really doesn’t match the performance you’d get from genuine RAM.