Discussion Forums > Technology

Cache on a dedicated SSD theory

(1/1)

Tatsujin:
So I stumbled upon this which features a PCI-E and got me wondering about few things. I don't have a clear idea of what "Cache" does exactly but I will just share my knowledge (correct me on these please). Cache works as a pre-loaded applications or programs that are on stand-by, and once launched they would quickly launch off of the specific folders. Am I right?

My other question is how do you control cache and to which driver would you refer it to? How good is "paging" on SSDs? Would it help ease your RAM a bit or would it be better to just shove everything on your RAM if you have tons of RAM?

datora:
.

--- Quote from: Tatsujin on January 03, 2013, 06:35:43 PM ---better to just shove everything on your RAM if you have tons of RAM?
--- End quote ---
^
THIS.

Cache is recently accessed data that is temporarily stored in a fastest access location for the CPU.  The fastest is the CPU L1 & L2 cache, then your RAM, then your SSD, then your HDD.  An SSD is so fast that it almost doesn't matter if or where the cache is located.  If you have 8GB or more of RAM, just worry about utilizing that as much as possible.  It won't hurt to have 4 or 8 GB of dedicated cache on the SSD, but you won't ever use it for most situations.  If you're working with huge files (video encoding, GB-sized images, etc.) or similar tasks, then it could possibly help a little.  On an HDD it will help, but on an SSD you're pretty much wasting space if you're not using it in a professional production environment.

Possibly some extreme games could benefit ... someone else with experience in that application will have to weigh in on it with an informed opinion.  I would expect 'probably not' since high-end video cards with something like 2 GB DDR5 memory should be much more suited for that task.

megido-rev.M:

--- Quote from: Tatsujin on January 03, 2013, 06:35:43 PM ---So I stumbled upon this which features a PCI-E and got me wondering about few things. I don't have a clear idea of what "Cache" does exactly but I will just share my knowledge (correct me on these please). Cache works as a pre-loaded applications or programs that are on stand-by, and once launched they would quickly launch off of the specific folders. Am I right?

My other question is how do you control cache and to which driver would you refer it to? How good is "paging" on SSDs? Would it help ease your RAM a bit or would it be better to just shove everything on your RAM if you have tons of RAM?

--- End quote ---

Cache is basically a way to reduce average access time for the CPU to access data on any given cycle, by really just copying the most relevant data to storage hardware more local to the CPU.

RAM serves like a cache for HDDs and SSDs in a way. The xDD's respective cache though only serves to reduce latency for accessing that xDD's data, and the RAM is still in the way to the CPU.

AFAIK you can't control hardware cache. Not even the OS could be able to do that.

Paging is just a way for the OS to run multiple programs via dividing the RAM into frames and mapping them to pages of each program's virtual address space. But what you're really thinking of is page swapping, and because it is not likely a page needs to swap out in large RAM, you're better off with larger RAM sticks.

mgz:
only possible problem i could see for using your SSD as cache is killing your ssd faster

halfelite:

--- Quote from: megido-rev.M on January 04, 2013, 04:12:57 AM ---


AFAIK you can't control hardware cache. Not even the OS could be able to do that.


--- End quote ---

You can have dedicated control over Hardware cache just not on your basic desktop machine once you get into enterprise class you can direct map, as well as  n-set on a hardware level if you know you need to, Also SSD burning out is no issue, no home machine would need anything like this setup, This would come in handy for large SQL based operations and anything needing fast access from 100,000's of connections. And anything in that type of setup hardware is swapped 2 years or less.

In your standard desktop computer your CPU might not even keep up with the 4MB or 8MB cache it has on its own dye, The cpu might max out all of its clocks on the first 2MB while the others sit idle. Huge amounts of RAM just keep the stress off the mechanical drive, while getting a little speed boost in terms of access times.

Navigation

[0] Message Index