HDD Cache

[Rienks]

32MB v 64MB v 128MB. What is the difference and what does it actually do?

[vanished]

32MB v 64MB v 128MB. What is the difference and what does it actually do?

My understanding is that for small IO tasks it can increase performance because the cache is quick memory like RAM or an SSD, and so if you try writing to it, it will just go there without having to invoke the slower platters & head.  Anything over that size needs to be immediately written however so more cache = higher performance, but only to a point.  IT's not going to improve sequential reads or writes very likely.

[Rienks]

My understanding is that for small IO tasks it can increase performance because the cache is quick memory like RAM or an SSD, and so if you try writing to it, it will just go there without having to invoke the slower platters & head.  Anything over that size needs to be immediately written however so more cache = higher performance, but only to a point.  IT's not going to improve sequential reads or writes very likely.

ty

[OddsCrazyStuff]

My understanding is that for small IO tasks it can increase performance because the cache is quick memory like RAM or an SSD, and so if you try writing to it, it will just go there without having to invoke the slower platters & head.  Anything over that size needs to be immediately written however so more cache = higher performance, but only to a point.  IT's not going to improve sequential reads or writes very likely.

 

"What is Disk Cache?

A portion of RAM used to speed up access to data on a disk. The RAM can be part of the disk drive itself (sometimes called a hard disk cache or buffer) or it can be general-purpose RAM in the computer that is reserved for use by the disk drive (sometimes called a soft disk cache). Hard disk cachesare more effective, but they are also much more expensive, and therefore smaller. Nearly all modern disk drives include a small amount of internal cache.

A soft disk cache works by storing the most recently accessed data in the RAM cache. When a program needs to access new data, the operating system first checks to see if the data is in the cache before reading it from the disk. Because computers can access data from RAM much faster than from a disk, disk caching can significantly increase performance. Many cache systems also attempt to predict what data will be requested next so they can place that data in the cache ahead of time.

Although caching improves performance, there is some risk involved. If the computer crashes (due to a power failure, for example), the system may not have time to copy the cache back to the disk. In this case, whatever changes you made to the data will be lost. Usually, however, the cache system updates the disk frequently so that even if you lose some data, it will not be much. Caches that work in this manner are called write-back caches. Another type of disk cache, called a write-thru cache, removes the risk of losing data because it only caches data for read operations; writeoperations are always sent directly to the disk."

 

Think that is a better explanation.

[Captain_WD]

32MB v 64MB v 128MB. What is the difference and what does it actually do?

 

Hey there Rienks,

 

The guys gave you a pretty good explanation of what the cache is used for. For everyday usage the difference between the three cache sizes is almost not detectable. You have to either work mainly with small files in order to see a significant improvement or to use the drive in servers, NASs and other workstations that constantly transfer small amounts of data and thus prevent the drives from spinning up for every single transfer or the need to spend time to find the data on the platter. 

What are you using the drive for? For regular home usage I'd recommend sticking with the common 64Mb.  

 

Captain_WD.

[Rienks]

 

Hey there Rienks,

 

The guys gave you a pretty good explanation of what the cache is used for. For everyday usage the difference between the three cache sizes is almost not detectable. You have to either work mainly with small files in order to see a significant improvement or to use the drive in servers, NASs and other workstations that constantly transfer small amounts of data and thus prevent the drives from spinning up for every single transfer or the need to spend time to find the data on the platter. 

What are you using the drive for? For regular home usage I'd recommend sticking with the common 64Mb.

 

Captain_WD.

 

Oh okay thank you Mr/Mrs/Miss/Ms WD representative much appreciated

 

Edit: I'm not sexist I swear

[Captain_WD]

Oh okay thank you Mr/Mrs/Miss/Ms WD representative much appreciated

 

Edit: I'm not sexist I swear

 

No problem If you need any other help, feel free to ask

 

Captain_WD.