Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →A flash memory cache is a faster flash-storage tier—usually an SSD—that keeps selected data from a slower storage device so later requests for that data can be served more quickly. It is not automatically extra storage capacity, and the phrase can also refer to an SSD’s internal write cache or to a computer’s separate, memory-based file cache.
What is flash memory cache?
In storage systems, a flash memory cache uses an SSD or another flash device as a faster layer in front of a slower backing store, such as a hard-disk drive (HDD) or storage pool. The system places selected data in the cache; the backing store remains the main source of the data. Linux device-mapper describes this pattern as dynamically moving data between a slower block device and a smaller, faster device such as an SSD: Linux kernel documentation on device-mapper cache.
As an Amazon Associate I earn from qualifying purchases.
Because the cache holds selected copies, its capacity should not be treated as a simple addition to the backing store’s usable capacity. Whether it improves performance depends on the workload and the cache policy.
How does SSD caching work?
Read cache: hits and misses
When a system receives a read request, it checks whether the requested data is already in the flash cache. A cache hit means it can serve the request from flash. A cache miss means it must retrieve the data from the backing store, which can be slower.
#1 Best Overall
- Get NVMe solid state performance with up to 1050MB/s read and 1000MB/s write speeds in a portable, high-capacity drive(1) (Based on internal testing; performance may be lower depending on host device & other factors. 1MB=1,000,000 bytes.)
- Up to 3-meter drop protection and IP65 water and dust resistance mean this tough drive can take a beating(3) (Previously rated for 2-meter drop protection and IP55 rating. Now qualified for the higher, stated specs.)
- Use the handy carabiner loop to secure it to your belt loop or backpack for extra peace of mind.
- Help keep private content private with the included password protection featuring 256‐bit AES hardware encryption.(3)
- Easily manage files and automatically free up space with the SanDisk Memory Zone app.(5). Non-Operating Temperature -20°C to 85°C
A cache may need time to warm up as frequently accessed data is identified. In its DSM 7.1 white paper, Synology describes an LRU (least recently used) replacement policy: when cache space is needed, the system can replace data that has gone unused longer. A shift in which data is frequently accessed can mean the cache needs to warm up again. This describes Synology’s implementation, not a universal rule for all SSD caches. See the Synology SSD Cache White Paper for DSM 7.1.
Write cache: two common policies
Write-cache policies determine whether a write reaches the backing storage immediately or later. Microsoft summarizes the two common modes as “write back and write through” in its documentation on querying for the write-cache property.
Rank #2
- Solid state performance with up to 800MB/s read speeds in a portable drive. (Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes.)
- Back up your content and memories on a storage solution that fits seamlessly into your mobile lifestyle.
- Take it with you on your adventures—up to two-meter drop protection means this durable drive can take a beating. (Based on internal testing.)
- Secure it to your belt loop or backpack for extra peace of mind thanks to the tough rubber hook.
- From Sandisk, a brand professional photographers trust to take on assignments.
- Write-back: The cache accepts the write first and updates the backing media later. This can improve write performance, but acknowledged data may be at risk if it has not yet reached the backing media and the cache loses power or fails. Protection depends on the particular device and storage system.
- Write-through: The write goes to the cache and backing media together. This does not improve write performance in Microsoft’s description, though keeping data in cache can help with later reads.
These terms describe a system’s cache policy. They are distinct from a write-through request that tells a device to bypass or flush a cache. The same Microsoft documentation covers that separate request and notes that a device write cache without battery backup can lose cached data during a power failure.
Does an SSD cache make a hard drive faster?
It can make some access faster when the requested data is in the cache; it cannot make every HDD operation faster. A cache is most useful when data are reused or when the cache policy fits the workload. If requests mostly concern data that are not cached, they still rely on the backing store. Cache size, warm-up behavior, and replacement policy also affect whether useful data remain available.
Rank #3
- NEARLY 2X FASTER THAN OUR PREVIOUS GENERATION(8) – move 1,000 high-res photos in under 60 seconds(6) with up to 2000MB/s transfer speeds(2).
- IP65 RATING AND UP TO 3M DROP PROTECTION(3) – protects against spills and drops.
- POCKET-SIZED – fits easily in pockets and small bags.
- SPACE TO OWN YOUR AI CONTENT – speed and capacity to download your high-res clips and photo edits.
- 256-BIT AES ENCRYPTION(4) – helps keep private files secure with password protection.
Platform details matter. Microsoft documents different cache behavior for Azure Local and Windows Server cluster storage pools: with all-flash deployments, NVMe cache is used for writes to SSD capacity drives; when rotating disks are used, the cache can cover both reads and writes. In that documented setup, reads from SSD capacity drives are generally served directly from those drives, while HDD reads may benefit from flash because HDDs have rotating-disk seek delays. These are Microsoft-described behaviors for those platforms, not a general specification for every NAS or server. Details are in Microsoft’s storage-pool cache documentation.
What is the difference between write-through and write-back caching?
| Policy | Where a write goes | Practical implication |
|---|---|---|
| Write-back | The cache receives the write first; the backing media is updated later. | Can improve write performance, but data not yet destaged to backing media needs protection against cache or power failure. |
| Write-through | The cache and backing media receive the write together. | Does not improve write performance in Microsoft’s description; cached data may help with subsequent reads. |
The implications above describe the modes documented by Microsoft; implementations can differ. Check the storage system’s documentation for its behavior and safeguards.
Rank #4
- MEET THE NEXT GEN: Consider this a cheat code; Our Samsung 990 PRO Gen4 SSD helps you reach near max performance with lightning-fast speeds; Whether you’re a hardcore gamer or a tech guru, you’ll get power efficiency built for the final boss
- REACH THE NEXT LEVEL: Gen4 steps up with faster transfer speeds and high-performance bandwidth; With a more than 55% improvement in random performance compared to 980 PRO, it’s here for heavy computing and faster loading
- THE FASTEST SSD FROM THE WORLD'S FLASH MEMORY BRAND: The speed you need for any occasion; With read and write speeds up to 7450/6900 MB/s you’ll reach near max performance of PCIe 4.0 powering through for any use
- PLAY WITHOUT LIMITS: Give yourself some space with storage capacities from 1TB to 4TB; Sync all your saves and reign supreme in gaming, video editing, data analysis and more
- IT’S A POWER MOVE: Save the power for your performance; Get power efficiency all while experiencing up to 50% improved performance per watt over the 980 PRO; It makes every move more effective with less consumption
Is SSD cache the same as an SSD’s internal cache?
No. “Flash cache” can refer to separate components or layers:
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →- Storage-level SSD cache: A flash device acts as a faster tier for data held on a slower backing device or pool.
- Device write cache: A cache within a storage device buffers writes before they are committed to nonvolatile media. Its policy and protection vary by device.
- System file cache: The operating system keeps file data in system memory to avoid repeated storage access. Microsoft’s File Caching documentation describes this memory-based behavior.
These layers can all reduce some storage-related delays, but they are not interchangeable. In particular, a computer’s file cache in RAM is not an SSD cache.
Best Value
- MADE FOR THE MAKERS: Create; Explore; Store; The T7 Portable SSD delivers fast speeds and durable features to back up any endeavor; Build your video editing empire, file your photographs or back up your blogs all in an instant
- SHARE IDEAS IN A FLASH: Don’t waste a second waiting and spend more time doing; The T7 is embedded with PCIe NVMe technology that brings fast read and write speeds up to 1,050/1,000 MB/s¹, making it almost twice as fast as the T5
- ALWAYS MAKE THE SAVE: Compact design with massive capacity; With capacities up to 4TB, save exactly what you need to your drive – from large working files to game data and everything in between
- ADAPTS TO EVERY NEED: Whether using a PC or mobile phone, count on the T7 for extensive compatibility²; It’s a true team player when it comes to heavy-duty application usage or file-saving
- HI RESOLUTION VIDEO RECORDING: Record Ultra High Resolution (4K 60fs) videos directly onto the T7 Portable SSD with your favorite camera or mobile devices; Supports iPhone 15 Pro Res 4K at 60fps video and more³
What should you check before choosing an SSD cache?
Compatibility and expected benefit depend on the platform and workload, so there is no universal SSD-cache specification that fits every NAS or server. Before configuring one, check:
- Platform compatibility: Follow the NAS or server maker’s compatibility guidance and supported configuration for cache drives.
- Workload: Consider whether the data are accessed repeatedly and whether the system is limited by reads, writes, or both.
- Endurance: Check the drive’s rated writes per day (DWPD) against the expected write workload.
- Sustained performance: Look at sustained random IOPS and latency consistency, not only peak or short-duration performance.
- Data protection: Understand what protects write-back data that has not yet reached the backing media.
Synology’s guidance discusses endurance and performance consistency as SSD-cache selection factors; those considerations do not establish a universal minimum drive rating. Its page also gives a product-specific DSM 7.1 example: an 800 GB SSD cache requires about 320 MB of system memory. That figure applies to the stated example, not to SSD caching generally. See Synology’s SSD cache considerations.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
