How much faster is memory (RAM) compared to SSD for random access? (2024)

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See https://www.quora.com/Is-the-speed-of-SSD-and-RAM-the-same:

Flash Memory is considerably slower than DRAM, and the way they are used by operating systems is very different.

A typical DRAM has a transfer rate of approximately 2-20GB/s, whereas typical SSDs have a transfer rate of 50MB-200MB/s. So it's one to two orders of magnitude slower.

Furthermore, the way it's used is very different. DRAM is far more flexible and is truly random access -- any word, any time. By comparison, flash writes have to erase an entire block at a time before writing to it; and there are other problems that need to be dealt with such as wear leveling and bad blocks.

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  The new ssd's getting pretty fast one example is: Intel's new P3608 Series PCIe SSD, The drive has a sequential read/write speed of up to 5,000MBps (5Gbps) and 3,000MBps (3Gbps), respectively.

  –Simon Dragsbæk

  Jul 19, 2018 at 7:50

• punchline - "any word, any time" :))

  –LiNKeR

  Sep 20, 2020 at 20:27

• Seems like RAMs have also gone tremendously more fast than the numbers mentioned in this answer (so have SSDs as mentioned in a previous comment). My source: youtu.be/o54YMz8zvCY?t=1399

  –akki

  Jan 15, 2021 at 1:55

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  With a (pro-) consumer grade SSD we're already at 7.2 GB/s at the time of writing. PCIe v4 with 4 lanes and a lot of fast flash.

  –Maarten Bodewes

  Jan 18, 2021 at 14:55

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6

Run memtest86, it displays numbers indicating memory read/write speed.

FWIW an Intel Atom 330 based mini-computer I currently have standing here says "1927MB/s" for the main RAM.L1 Cache is 3748MB/s, L2 Cache is 3095MB/s, there is no L3 Cache.

These speeds will vary with CPU and computer design.

A google on "SSD disk speed" will tell you numbers to compare with; expect anything from speeds similar to fast HDD's (100-150MB/s, slow SSD) and up.

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DRAM is much faster than any SSD or other solid state storage device. Generally, you can put it to be at least 5-10 times faster, depending on frequency, generation and the SSD you are comparing it with. SRAM is even faster than DRAM, at least a few times more.

To get some sort of comparison, you can set up a RAMdisk on the target machine and then benchmark both the SSD and the RAM. You can get some information on this here:

http://www.pcworld.com/article/260918/how_to_supercharge_your_pc_with_a_ram_disk.html

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