SSHD, not understanding

[somebody301]

Hi,

I'm not understanding what SSHD are and how they work. I mean I know that they are made by a HHD + SSD used as a cache... However, I know that in HDDs drives there's a small buffer, usually 16MB or 32MB that act also as a cache.

I'm not understanding if the HDD drive with that kind of buffer is considered a Hybrid drive or, if a Hybrid drive is actually the hard disk + SSD with a bigger capacity.

Thanks.

 

[amir_1991]

Hi,

I'm not understanding what SSHD are and how they work. I mean I know that they are made by a HHD + SSD used as a cache... However, I know that in HDDs drives there's a small buffer, usually 16MB or 32MB that act also as a cache.

I'm not understanding if the HDD drive with that kind of buffer is considered a Hybrid drive or, if a Hybrid drive is actually the hard disk + SSD with a bigger capacity.

Thanks.

The buffer is not a SSD drive, it's just help to speed up the hard disk I/O to be near cpu and memory speed, but SSHD drives has a 8GB SSD that let you to achieve more speed of read and write the files you usually use them.

 

[SuperSoph_WD]

Welcome to the community, somebody301!

@Amir made a good point about the difference.
There are some common aspects of a buffer and a cache, however, they are very different.
The buffer is a part of the primary memory (RAM). This region of physical memory storage is used to temporarily hold data while it is being moved from one place to another. A buffer ends up cycling through and holding every single piece of data that is transmitted from one storage location to another. The buffer size depends on the model of the hard drive. Larger buffer sizes are definitely beneficial for reading and writing, however, you won't be able to really notice the difference, except if you put 2 identical HDDs with different buffer sizes side-by-side in your system. They are still mechanical drives, though, and they still won't outperform a hybrid drive.

The purpose of the SSD cache is to store the data in a transparent way. As @Amir mentioned hybrid drives use a specific SSD technology that built-in the mechanical HDD. This built-in NAND flash SSD tech enables the hybrid drive to perform up to 4-5 times faster than traditional desktop drives. The SSHD firmware is also different than other mechanical hard drives. By utilizing an advanced set of algorithms, it allows the drive to prioritize by itself frequently used data, thus you're able to boot into the OS much faster in comparison to traditional desktop HDDs.

Hope this was helpful. Keep us posted if you have more questions!
SuperSoph_WD

 

[somebody301]

So, the hybrid drive will select the files and data that are most accessed and then it will store in the SSD rather than in the mechanical drive, in order to speed up the system. And, a bigger buffer mean more data transferred in the RAM by shot, but considering that there's no much difference between 16Mb and 32Mb it won't be a huge advantage unless you will handle data constantly. They are totally different tough.

Another good question comes with the SSD caching: if you have a hybrid drive would another SSD drive used as a cache worth it?

 

[cst1992]

You'd then store the OS on the SSD itself; so that you always get SSD-class startup times.

However, don't select a SSD size that'll get your SSD filled up by the OS alone(such as a 60GB variant). SSD's slow down the more they're filled.

SSHD's are middle ground for people not wanting/able to afford to spend extra on an SSD(such as getting a 2TB SSHD for $150 when a plain 2TB HDD sells for $100). If you can spend the $100 for an SSD, get that instead. (all prices as an example, prices in the US are certainly lower than this).

 

[somebody301]

I think that a bigger SSD may be the best choice, especially if I will be doing some audio/video processing and gaming. However, first thing first: I need to improve my internet connection right now (and getting rid of a really frustrating issue), but this is another thread.

About the SSD price, the best one I've came across is a 980Gb at 320 Eur (OCZ ssd on SATA).