What is the difference between HDD, SSD and GDDR Type of memory technologies?
In: Technology
HDD is magnetic. It’s stable at rest and physical.
SDD is electrostatic, with very slow decay. It’s stable-ish at rest, but not a physical change.
GDDR is electrostatic, but it requires active refresh because it decays in milliseconds.
With the two storages, HDD’s are Hard Disk Drives meaning they have a magnetic platter with reading heads on multiple sides of it spinning at a few thousand or more RPM when they are on and capable of reading and writing to their storage. Usually shaped like an H where it reads on all four surfaces of the H minus the center axis, the horizonal line. SSD’s are Solid State Drives and a form of storage fairly similar to a memory card or SD card, there are zero moving parts within it, but SSD’s meant for computers have a lot better read and write speed than a simple SD card. Good HDD’s and SSD’s will actually have another form of memory similar to RAM called cache to help smooth out the gaps in read/write behavior.
GDDR on the other hand is a form of RAM that is utilized by your graphics processing unit and it is not exactly the same as the DDR you’d find plugged in next to your CPU or central processing unit, GPU’s and their memory are optimized to handle their niche workload better than the CPU and system RAM.
Basically the GPU is doing math with slightly different equations to handle what its working on better than the other processing units, and the GDDR RAM is tuned to be filled by this data particularly well. Also those equations let the GPU chip be clocked at higher speeds than an equal slab of silicon manufactured as a CPU could withstand safely.
An HDD works similar to magnetic tape (like VHS and audio casettes), except that the magnetic material is applied to a bunch of spinning disks instead of a spool of tape. The data is stored by changing the magnetic orientation on the disk, and read by detecting the magnetic field.
An SSD uses flash memory, that is tiny cells etched onto a silicon chip, which can trap an electric charge. Think of billions of microscopic batteries on a small chip: If the battery is full, it’s a 1, and if it’s empty, it’s a 0. Both hard disks and SSDs can store their data for a very long time, which is why they are so widely used for storage.
GDDR is a type of volatile memory used for graphics cards. That means it uses small transistor circuitry to store data, the so called “flip flops”. A flip flop works like a light switch: You flip it on, and it stays flipped. Flip it off, and stays flipped off. However, instead of a metal spring, this particular light switch uses an electric motor to remember whether it was on or off – and if the power goes out, you lose all data on it.
It is possible to store data permanently using volatile memory, but this needs a continuous power supply to work. This is sometimes used for very high performance server applications where hard disks aren’t fast enough and flash memory would be worn down too quickly.
HDDs and SSDs are both storage drives that store data even when not powered. They are MUCH slower than RAM which is what GDDR is. RAM loses all of its data when turned off. In addition storage is storage is relatively inexpensive compared to RAM. If you look at 1tb of an HDD it might cost around 40-50$. For that same price you only get around 16gb of ram. For reference ~1000gb = 1tb.
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