Solid state drives (SSDs) have become an essential component for any high performance computer system. With no moving parts and much faster read/write speeds compared to traditional hard disk drives (HDDs), SSDs can dramatically improve system boot times, application launch times, and overall system responsiveness. When shopping for an SSD, factors like capacity, performance, endurance, and price should be considered to find the best option for your needs and budget.
What is an SSD?
An SSD is a storage device that uses flash memory chips to store data persistently, similar to a HDD. But unlike a HDD, an SSD has no moving mechanical components, allowing it to operate silently and tolerate more physical shock. Data is stored in memory cells that retain charge without power, unlike volatile RAM that loses data when power is removed. Reading data simply requires sensing the cell charge states, and writing data involves programming cells to desired states. This enables much faster data access compared to HDDs.
Some key advantages of SSDs over HDDs include:
- Faster read/write speeds – SSDs can achieve sustained read/write speeds of 500-3500 MB/s, compared to 80-150 MB/s for HDDs.
- Lower access times – SSDs can access data in microseconds, while HDDs require milliseconds.
- Better shock/vibration tolerance – No moving parts makes SSDs more durable.
- Lower power consumption – SSDs use less energy than HDDs.
- Silent operation – No moving parts means no audible mechanical noises.
- Compact and lightweight – SSDs have higher storage density.
However, there are some downsides:
- Higher cost per gigabyte – SSDs are more expensive than HDDs for an equivalent capacity.
- Limited number of write cycles – Flash memory cells wear out after repeated programming.
Overall, the dramatically faster speeds make SSDs ideal for applications where performance is critical, such as the primary boot drive for an operating system. The higher cost makes them less suitable for bulk storage needs, where HDDs are slower but much more cost effective at higher capacities. Most computers today utilize both SSDs and HDDs in a complementary fashion.
Types of SSDs
There are several types of SSDs that utilize different interfaces and technologies:
SATA SSDs connect via the SATA interface, just like HDDs. This allows them to easily replace HDDs in computers and utilize existing SATA infrastructure. SATA SSDs typically come in the 2.5-inch form factor common for laptop drives, but 3.5-inch desktop form factors are also available. SATA interface speeds cap at around 600 MB/s. Some examples of SATA SSDs include:
- Samsung 870 EVO
- Crucial MX500
- WD Blue 3D NAND SATA SSD
M.2 SSDs utilize the M.2 connector standard, designed specifically for SSDs. M.2 allows PCIe and/or NVMe interfaces for much faster speeds compared to SATA. M.2 SSDs come in a compact circuit board form factor designed to mount directly onto motherboards or expansion cards. Some examples of M.2 SSDs include:
- Samsung 970 EVO Plus
- WD Black SN750
- Crucial P5 Plus
PCIe SSDs connect directly to a PCIe slot on the motherboard via a mounting bracket. This provides even greater bandwidth compared to M.2 slots, allowing maximum SSD performance. However, they occupy a larger footprint. Examples of PCIe SSDs include:
- Samsung 980 Pro
- WD Black AN1500
- Seagate FireCuda 520
NVMe vs AHCI
NVMe and AHCI refer to communication protocols that SSDs can use when connected via PCIe interfaces. NVMe is newer and designed specifically for SSDs, while AHCI was designed for HDDs. NVMe allows much higher performance – around 3500 MB/s max vs 600 MB/s max for AHCI. Most new SSDs today support NVMe, while AHCI compatibility allows use in older systems.
SSD Form Factors
Some common form factors for SSDs include:
This smaller form factor is designed to fit in the same drive bays as 2.5-inch laptop HDDs. They require a SATA interface and fit into both laptops and desktops.
Compact M.2 SSDs are designed to mount directly on motherboards and expansion cards. Different length (16mm to 110mm) and width (22mm or 22×42/60/80mm) options are available.
Add-in card (AIC)
AIC form factor SSDs add storage capacity through dedicated expansion card slots. Examples include full-height half-length PCIe cards.
A newer form factor that allows for hot-swappable 2.5-inch SSDs through a U.2 connector. Similar in size to 2.5-inch drives but delivers PCIe speed.
SSD Performance Metrics
Some key specifications help determine real-world SSD performance:
Sequential Read/Write Speed
The maximum sequential data transfer speed when accessing large contiguous blocks of data. Important for large file transfers.
Random Read/Write Speed
The speed when accessing small random blocks of data. Affects small file access and OS/program responsiveness.
IOPS (Input/Output Operations Per Second)
The number of I/O operations possible per second. Relevant for workloads involving many small random I/O requests.
The delay between requesting data and receiving it from the SSD. Lower latency provides snappier responsiveness.
The total bytes of data that can be written over the SSD’s lifetime. Determined by NAND quality and controller.
Higher tier SSDs offer improved performance and endurance through advanced controllers, NAND flash quality, and newer interfaces like PCIe 4.0 x4 lanes.
Ideal SSD Use Cases
SSDs excel in these common scenarios:
An SSD dramatically reduces OS and program loading times compared to HDDs due to faster random I/O speeds. Using an SSD as the primary boot drive provides a very noticeable improvement in system responsiveness.
Frequently used applications and games
Applications and games loaded from an SSD benefit from faster load times. The faster speeds also improve level loading and texture streaming in games.
Scratch disks for content creation
For photo/video editing and 3D rendering, SSDs enable much faster access to temporary scratch files, improving workflow.
The high random I/O performance of SSDs can better support many virtual machines running on hypervisor servers.
Important SSD Buying Considerations
Here are some key factors to consider when selecting an SSD:
Are you looking for a smaller capacity boot drive or a high capacity storage drive? For boot, 250GB-500GB is common, while 1TB+ is preferred for gaming and production storage.
Does the SSD need to fit specific size constraints? M.2 for compact and modular builds, 2.5-inch for laptop drive bays, Add-in card for maximizing capacity.
SATA provides up to 600MB/s and compatibility with older systems, while PCIe 3.0/4.0 x4 enables speeds up to 5000MB/s for new PCs. NVMe is preferred over AHCI.
Faster sequential and random speeds deliver snappier loading and responsiveness. IOPS ratings quantify random I/O capability. Pick an SSD tier appropriate for your budget.
Higher write endurance improves lifespan for write-intensive workloads. Look for TBW (terabytes written) ratings.
Manufacturer and Controller
Reputable brands with quality controllers yield optimal reliability and sustained write performance.
5-year warranties provide assurance of longevity. Longer coverage periods indicate higher confidence in reliability.
Price per GB
For bulk storage, the ideal balance of cost, capacity and performance may be preferred based on budget.
Match the SSD’s strengths to your specific needs – OS/programs vs. high capacity storage vs. scratch disk vs. caching, etc.
Best Crucial SSDs Compared
Crucial makes some of the most popular and well-reviewed SATA, M.2, and PCIe SSDs for consumers and enterprises. Here is how some of their top models compare:
|SSD Model||Form Factor||Interface||Capacity||Seq. Read MB/s||Seq. Write MB/s||Random Read IOPS||Random Write IOPS|
|Crucial P5 Plus||M.2||PCIe 4.0 x4||Up to 4TB||6600||5000||800K||700K|
|Crucial P5||M.2||PCIe 3.0 x4||Up to 2TB||3400||3000||240K||540K|
|Crucial P2||M.2||PCIe 3.0 x4||Up to 2TB||2400||1800||230K||260K|
|Crucial MX500||2.5-inch||SATA||Up to 2TB||560||510||95K||90K|
The P5 Plus is Crucial’s top performer, leveraging the latest PCIe 4.0 interface and advanced controller to deliver sequential speeds over 6GB/s along with very high random I/O performance. It provides elite-class throughput for high-end gaming and production use.
The P5 and P2 offer excellent PCIe 3.0 performance at more affordable price points, making them great OS and gaming SSDs. And the mature MX500 remains a budget-friendly SATA pick.
In summary, an SSD can tremendously accelerate a computer system by removing storage bottlenecks. When selecting an SSD, consider your capacity needs, form factor, interface support, performance requirements, workload endurance, manufacturer reputation, warranty protection, and budget.
Crucial SSDs like the P5 Plus, P5, P2, and MX500 provide an excellent balance of cutting-edge performance and proven reliability. For most consumer systems today, an M.2 PCIe 3.0 SSD like the Crucial P5 delivers compelling speed for gaming and professional workloads while minimizing cost. But if building a new high-end desktop with PCIe 4.0 support, the P5 Plus tops the benchmarks. Ultimately, matching a quality SSD like Crucial’s lineup to your specific computing needs and goals will let you fully leverage the transformational performance advantages of solid state storage.