What Is SSD Cache?
SSD cache or as it’s correctly termed, SSD caching, is a data management mechanism developed by Intel in the early 2010s that uses a small solid-state drive as a cache for a generally larger hard disc drive.
A cache is hardware or software memory designed to store commonly used data for easy, fast access. In the case of CPUs, the cache consists of flash memory that is faster to access than standard system RAM, while browser caches store components from frequently visited sites so that they load quicker negating the need to retrieve data across the internet from the hosting server.
As such, a cache allows the system to access data much faster than if it was retrieved and read from its final resting place on an HDD resulting in improved performance for memory dependent tasks.
For SSD caching, the core concept is to provide a much faster and more responsive SSD as a temporary storage unit for frequently requested data such as basic OS operational scripts and files that are stored on a slower conventional hard drive. The speed of an SSD is to a magnitude of about ten times that of an HDD for most tasks with SSD faring intrinsically better for random access small disk reads that define the bulk of everyday tasks within an OS.
In real terms, SSD caching would involve a small-sized SSD, say 40GB, in tandem with a larger traditional HDD with for, example, 1TB of storage.
SSD Caching Compatibility
Intel coined the SSD caching technology Smart Response Technology (SRT), and the proprietary iteration of the mechanism is only available on SRT-ready motherboards with Intel chipsets. To make matters worse, Intel doesn’t run the technology of all its chipsets, which limits the hardware configurations the user can expect to have while still being able to run SSD caching.
Systems with AMD chipsets require the user to use third-party software to emulate SSD caching as AMD has not developed or integrated a rival technology into their chipsets to date. Fortunately, there are numerous software solutions such as FancyCache and PrimoCache. They are, however, notoriously unreliable and cough up a litany of issues.
SSD Caching Limitations
SSD caching provides a tangible benefit only when a system is in what we term a ‘’clean’’ state such as booting up a PC after it’s been off, rebooting Windows, or the initial running of an application after a restart or power down. There’s a memory hierarchy that runs from the CPU cache, to RAM, SSD cache, then HDD. A restart wipes clean the CPU cache and RAM, making the SSD cache the go-to location for data.
The reason for this is that in all other cases, the chances are that crucial, frequently accessed data is already being stored by the system RAM and as RAM is staggeringly faster than any hard drive storage, be it SSD or HDD, the SSD caching does nothing to improve speed as the data is already available much faster from the RAM.
As you can see, the main benefit of SSD caching is most apparent when booting up Windows: the OS is in a usable state much sooner than on a non-SSD cached system. Similarly, launching Steam and your favorite game after a reboot will be much faster with SSD caching. If you’ve been running without a restart for multiple hours and have opened then closed various programs and decided to open them once more, SSD won’t do anything to speed up the process.
Continuing on the theme of limiting factors, the inner workings of SRT are a closely guarded secret, and Intel provides no details about how the technology vets what data is worthy of caching, although perceptible trends suggest there is a definite cap on the size of data that can be cached weighing in a handful of MB at most.
For anything heftier, the system will revert to the slower HDD source for data. From the user end, this means programs that rely on small data packets work well, while those that depend on capacious media like video and high-quality audio files don’t.
If you run a host of applications simultaneously the benefits will be apparent, while if you run the same program day in, day out handling large format files, the advantages will be marginal.
Is SSD Caching Worth It?
Once SSD caching is up and running, it takes care of itself with next to no input from the user. The benefits, if there are any, are passively produced, which makes it a hassle-free solution.
However, setting up caching, even with an Intel SRT chipset is an arduous task that involves using the correct drivers, configuring the BIOS appropriately and running it as a RAID setup, installing Windows and the Rapid Storage Technology drivers, managing modes, etc. The bottom line is that it is significantly more involved than using a large capacity SSD and simply installing Windows.
SSD caching has historically cost much less than splashing out for a reasonably sized SSD, but as the technology becomes increasingly ubiquitous, the price of even 100GB or more SSDs is exponentially more affordable as time progresses. Consequently, the SSD cache and HDD combination is being replaced by larger, budget SSDs as the home for the OS, while a larger HDD is used for media storage that is infrequently accessed.
Similarly, the advent of hybrid SSDs or SSHDs has also put a dent into the popularity of SSD caching. An SSHD is none other than a conventional HDD fitted with a portion of flash memory, known as NAND. These two parts are integrated and form part of the same data storage solution. In practice, the flash memory monitors user activity to determine which applications, data, boot elements, and so on are most frequently accessed, and then stores these significantly speeding up system performance.
In our estimation, the core concept behind SSD caching is worth pondering over. In practice, the results aren’t pronounced enough to opt for SSD caching over spending marginally more for a larger SSD and running everything from Windows to your favorite shooters from the very same drive and letting the RAM do its magic unperturbed.
The UK-based journalist and gamer, Thomas, describes himself as a man of few words with an unhealthy obsession for everything wonderful about the world of gaming. Thanks to his experience in the gaming industry, he brings a wealth of talent into GamingScan.