why is ram so fast?
In: Technology
RAM is designed and connected differently.
The design trades off guarantees your hard drive makes (correctness, stability) for speed. This is possible because RAM isn’t used for the same jobs – it provides a small fast space where you can quickly compute or change things.
The connection is also different, using dedicated broad connections to your CPU that make accessing it much faster. Compare the number of pins (individual connections) on a RAM stick to those on SATA or PCI slots – RAM has 144 to 380, while PCI has fewer than 60. This means that more data can be moved across at once, allowing for faster transfer speeds.
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RAM doesn’t _always_ make the same trade offs. ECC RAM, for example, gives you better guarantees ability the stability of memory compared to normal consumer-grade RAM. This is often found in servers and is stable enough that you can boot from it, making it effectively closer to hard drive quality with RAM connection speeds. Very expensive though.
Additionally your OS might make RAM somewhat more confusing, as it can trade memory from RAM to disk using page files. This gives more stability (at the cost of performance) as well as allowing programs to use more memory than there is available RAM.
No moving parts. Unlike a common harddrive you don’t have to wait for data to be physically retrieved.
Because it is addressed pretty much directly by the cpu the cpu can just ask for an address and immoderately access the data
I don’t know how it works with pcie ssds, but I’m pretty sure they have to do more complex requests
no moving parts is one reason
the other reason is that RAM has special access to the CPU thru the main Bus which is way faster than normal storage connections(generally a multiple or submultiple of the CPU’s clock speed)
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