Is SSD or HDD better for recording, or are they the same?

[DontEvenAskMeMyUsername]

Hey,

I just recently had a random question pop into my head. Is an SSD better for recording, or an HDD? Or are they the same? I'm not really talking about which one is better in terms of speed. What I mean is the way they function, wouldn't an HDD be better, or at the very least, just as capable as an SSD? An SSD works by using sectors to write to that can do it, and there's nothing holding it back. Compare that with an HDD, which uses a hand to read and write data to a CD-like thing. The SSD sounds better, since in a race from the front of the disk to the back, the SSD wouldn't have to move a muscle unlike an HDD. It's basically teleportation (SSD) vs running (HDD). However, why I'm asking this is because of how the drives work AND how recording works. When you record, it's basically flying through the disk writing the data it records. An SSD could probably do a great job, but wouldn't an HHD do just as good as a job if not better? An SSD essentially is able to teleport between sectors while the HDD has to essentially run through the disk. But if I'm using OBS (which I actually do personally) and it's writing to the drive continuously at a stable speed at, say, 5000Mbps, wouldn't they basically be going the same speed? The SSD would be teleporting tons of times per second while the HDD is just running, and at the same speed too. Wouldn't the HDD be the same if not better? Heck, why hasn't recording softwares implemented a way to tell the software to record at a set RPM using an HDD, since HDD speeds are calculated by RPM?

Thanks,
DontEvenAskMeMyUsername

 

[boosted1g]

Assuming the data written was not getting near maxing out the HDD write speed then for sequential recording it would not make a diffence.

However, as your HDD gets writen, overwritten, writen, overwritten, the new recording wont be written in 1 continous block but in several chunks accross the drive, at that point the SSD would be better.

Now if there are not many chunks and bitrate is not reaching limits of HDD then there would be little to no noticable difference.

 

[rkzhao]

What you are describing is sequential performance vs random performance. You are thinking the right way in that for random operations SSDs can essentially "teleport" around while a mechanical HDD really suffers due to the physical movement required. However, even on sequential operations, a SSD is still faster because an HDD is also limited by the spinning disk, as well as simply the amount of time it takes to program the data to the media.

Firmware overhead also plays a factor in determining the final performance we see. So while an SSD doesn't require any physical movement for random operations, there is still some additional overhead in the firmware when compared to purely sequential operations, which is why sequential performance is still better.

Now back to the question at hand, if your system is not requiring the performance capabilities of an SSD, that takes away one of the main benefits of an SSD. It's like comparing a Prius to a Corvette when the requirement is simply for cruising at a constant speed of 45mph.

There are still other factors at play so it's hard to say what's better. SSDs are less suceptible to the same type of physical disturbances that a HDD might be. Things like shock, vibration, and environmental factors. SSDs are quieter since there's no mechanical movement. SSDs are more prone to heating issue when pushed but at lower speeds, it's not likely to happen. SSDs are more susceptible to external electrical issues like voltage spikes and sudden power losses. SSDs have a more limited lifespan when it comes to the amount of times they can be re-written. SSDs are obviously much more expensive.

You're pretty much looking at why SSDs aren't completely replacing HDDs any time soon in the industry. There are many applications where it's simply not worth it to use an SSD.

Oh as for variable RPM, I think that exists, at least for power saving reasons. Slowing down the disk reduces power consumption and noise. However, to have the drive operate with a variable RPM adds a whole ton of complexity in both the hardware and firmware which would drastically increase design and manufacturing costs. It's simply not worth it if it undermines the main advantage HDDs have over SSDs, cost.