When it comes to choosing a hard drive for your computer, there are two main options to consider: hard disk drives (HDD) and solid state drives (SSD). Both have their advantages and disadvantages in terms of performance, durability, price, and use cases. This article will compare HDDs and SSDs to help you determine which hard drive type is the better choice for your needs.
What is a Hard Disk Drive (HDD)?
A hard disk drive (HDD) is a traditional storage device that uses magnetic storage to store and retrieve digital information. Data is written to and read from quickly rotating platters coated in magnetic material. A read/write head floats just above the platters reading and writing data.
HDDs have moving parts which make them susceptible to damage from drops or bumps. The platters spin at high speeds of 5,400 to 15,000 rpm in desktop and laptop PCs. Because of the moving parts, there is a risk of failure over time which increases with use. HDDs gradually become fragmented which can degrade performance.
Advantages of HDDs
- Cheap per GB – HDDs offer more storage capacity per dollar compared to SSDs.
- High capacity – Consumer HDDs are available in capacities up to 16TB for desktops.
- Proven technology – HDDs have been around for decades and are a mature, well-understood technology.
Disadvantages of HDDs
- Slower speeds – HDDs have slower data transfer speeds, especially for random access due to moving parts.
- Noise and vibration – The spinning platters and moving heads make audible noise and vibrate.
- Heat production – Friction from moving parts generates more heat which needs to be dissipated.
- Failure risk – The mechanical parts can fail, especially with impacts or age.
What is a Solid State Drive (SSD)?
A solid state drive (SSD) is a storage device that uses integrated circuit assemblies to store data persistently. It typically uses NAND flash memory chips that retain data even when power is turned off. SSDs have no moving mechanical components and are designed to withstand vibration, shocks, and high temperatures.
Data is stored in blocks of memory cells. Read and write operations are very fast since latency is low. SSDs use less power and run silently since no spinning platters or moving heads. Fragmentation doesn’t degrade SSD performance like HDDs.
Advantages of SSDs
- Faster speeds – SSDs have much faster data transfer speeds and access times. Boot and load times are far quicker.
- More durable – With no moving parts, SSDs can better withstand vibration, shocks, bumps and drops.
- Quieter – SSDs make no noise and don’t vibrate since there are no spinning disks or moving heads.
- Lower power – SSDs consumer much less power resulting in longer battery life for laptops.
Disadvantages of SSDs
- Expensive per GB – SSDs are more expensive per gigabyte than hard drives.
- Lower capacities – Consumer SSD unit capacities typically top out at 4TB currently.
- Wear over time – SSDs can wear out after a large number of program/erase cycles. consumer SSDs are rated for up to 600 TBW.
Comparing HDD and SSD Performance
SSDs significantly outperform HDDs when it comes to data transfer speeds and access latency. This is because SSDs don’t have to move mechanical parts to locate and retrieve data. Let’s compare the specs of a typical consumer HDD vs SSD:
| Spec | HDD | SSD |
|---|---|---|
| Sequential Read Speed | Up to 210 MB/s | Up to 550 MB/s |
| Sequential Write Speed | Up to 210 MB/s | Up to 520 MB/s |
| Random Read Speed | Up to 2 ms seek time | 0.1 ms access time |
| Random Write Speed | Up to 2 ms seek time | 0.1 ms access time |
As you can see, the SSD has much faster sequential read/write speeds of around 550/520 MB/s respectively compared to 210 MB/s on the HDD. More importantly, the SSD’s random access times are extremely fast at 0.1 ms vs 2 ms on the HDD.
This means tasks like booting up and loading programs and files happen much faster with an SSD. Activities like installing apps, copying files, transferring data, and multitasking greatly benefit from the SSD’s performance advantages.
Comparing HDD and SSD Reliability
SSDs are generally more durable and reliable than HDDs due to the absence of moving parts. HDDs can fail due to mechanical faults like:
- Failed read/write heads
- Motor failure
- Degraded ball bearings
- Damaged platters
Shock damage is also a risk with HDDs. SSDs don’t have these failure points and are more resistant to shock, vibration, temperature, and magnetism. However, SSDs do experience wear as memory cells degrade with use over time. Consumer SSDs typically have endurance ratings of 100 to 600 TBW.
Both HDD and SSD reliability are measured in annualized failure rate (AFR). AFR represents the percent of drive failures out of the total population in a year. Enterprise-class HDDs have AFR between 0.55% to 0.73%. Enterprise SSDs AFR ranges from 0.03% to 0.44%. So SSDs are less likely to fail in a given year.
Overall, SSDs are more reliable than HDDs long term. But HDD reliability is still very good for modern drives. Both HDD and SSD reliability can be further improved by purchasing drives rated for 24/7 operation and wider temperature ranges.
Comparing HDD and SSD Durability
Again, SSDs win when it comes to durability and lifespan. Because they have no moving parts, SSDs better withstand shock, vibration, dust, temperature changes, and magnetism. Dropping a SSD onto a hard surface has virtually no effect on its operation.
HDDs have to park read/write heads during impact to avoid scratching platters. While modern drives have accelerometers and ramps to mitigate this problem, it’s still a risk. The mechanical parts in HDDs simply wear out over time.
SSD lifespan is harder to predict. It depends on how much data is rewritten over time. Consumer SSDs typically have endurance ratings between 100 to 600 TBW. Heavy workloads may only last a few years, while light usage can mean SSDs operate reliably for over a decade.
So while HDDs have largely predictable lifespans dependent on mechanical wear, SSD lifespan varies greatly based on usage. Light SSD usage allows drives to operate for many years thanks to their resilience against physical wear.
Comparing HDD and SSD Price
HDDs continue to offer far more storage capacity per dollar spent compared to SSDs. For example, a 16TB HDD costs around $300 while a 16TB SSD costs over $2,000. For bulk storage needs on a budget HDDs can’t be beaten.
Smaller capacity SSDs are more reasonably priced. For instance, a 1TB SSD costs around $80 while a 1TB HDD costs around $40. The price premium for SSDs is worth it for many, especially when used as a boot or program drive. But HDDs offer affordability for mass storage.
SSD pricing has been gradually improving. According to a leading market research firm, SSD average selling prices per GB declined from $0.46 in 2015 to $0.09 in 2020. As manufacturing costs continue to fall, SSD pricing will become more competitive versus HDDs.
Right now HDDs are the value leaders for bulk storage while SSD prices are becoming more attractive at lower capacities where speed is needed. Expect SSDs to slowly gain share as prices fall, especially for boot drives, PCs, and laptops.
Comparing HDD and SSD Noise
HDDs produce noise from spinning platters and moving read/write heads while SSDs are completely silent since they have no moving parts. The sound profile of HDDs includes:
- Hum or whine from spindle motor
- Scratching noise from head moving
- Low frequency noise when platters spin
Noise levels vary greatly between HDD models from near silent to audible humming/whirring. Noise is measured in A-weighted decibels (dBA). Quieter HDD models rate around 20 dBA while noisier drives are around 30 dBA.
SSDs have no noise at all (0 dBA). This makes them better suited for noise-sensitive environments like studios, medical devices, and data centers where HDD noise could be disruptive. SSDs are also preferred for quiet environments like a bedroom or study.
Comparing HDD and SSD Power Efficiency
SSDs use less power and run cooler than HDDs. exact power usage depends on the specific drive, but let’s compare typical values for a 3.5-inch desktop HDD vs. 2.5-inch SSD:
- 3.5-inch HDD: 6 – 10 Watts idle, 10 – 14 Watts active use
- 2.5-inch SSD: 0.1 – 0.5 Watts idle, 1 – 4 Watts active use
The SSD uses maybe 15% of the power of the HDD. This is because SSDs don’t have to physically move parts which takes considerable energy. Less power draw also means less heat is generated. SSDs typically operate at 30° – 45°C versus 35° – 55°C for HDDs.
Lower power consumption and cooler operation lets SSDs work well in small form factor devices and increase laptop battery life. HDDs require more space for cooling and ventilation which makes them less suitable for compact devices.
Comparing HDD and SSD Form Factors
While HDDs have traditionally used large 3.5-inch desktop and 2.5-inch laptop sizes, SSDs are found in a much wider array of form factors. Common SSD form factors include:
- 1.8-inch microSATA
- 2.5-inch SATA
- M.2 stick
- mSATA
- U.2
Having no moving parts allows SSDs to be made much smaller than HDDs. The compact M.2 form factor is ideal for ultrabooks and small form factor PCs. The small size enablesIntegration onto motherboards. Their versatility allows SSDs to be used in more systems.
HDDs are limited to mostly traditional larger form factors focused on desktops and laptops. While HDDs are also available in smaller form factors, their capacities max out much lower. HDDs remain essential for affordable mass storage, while SSD versatility opens more applications.
SSD and HDD Availability
While HDDs ship in far greater volumes than SSDs, both have excellent availability. As mass storage, HDDs represent 85% of the total hard drive market. SSDs are 15% share but growing. Raw HDD shipments were over 350 million units in 2021 versus 67 million SSDs.
Virtually every laptop and desktop ships with HDD storage. Bulk HDD availability makes them easily purchased from online retailers, tech outlets, and manufacturers. SSD availability is also strong, though supply chain challenges in 2022 temporarily constrained NAND flash supply.
Since HDDs and SSDs utilize completely different technology, production is not an either/or proposition. HDDs dominate mass storage, while SSDs are top choice for performance-centric computing. This complementary demand ensures steady availability of both going forward.
Choosing Between HDD and SSD
So which is the better choice – HDD or SSD? There is no universal answer, as each technology has strengths and best uses. Some guidelines for choosing between them:
- Boot/programs drive – SSD is strongly preferred for boot and program storage thanks to faster speeds.
- Gaming rigs – SSD is recommended for storing games to load levels faster.
- High capacity storage – HDD is better for affordable bulk storage of media files, documents, etc.
- Desktop vs. laptop – SSD preferable for laptops thanks to lower power, heat, and smaller sizes.
- Critical data – SSD better for protecting key data from shocks, vibration, temperature.
- Noise – SSD if HDD noise is distracting in a quiet workspace or for audio recording.
- Budget – HDD is significantly cheaper per terabyte for capacity.
Many systems combine an SSD boot drive with an HDD for storage to get the best performance and value. With SSD prices declining and capacities growing, all SSD systems are becoming more viable for mainstream users.
Conclusion
Solid state drives outperform hard disk drives on key metrics like speed, durability, noise, and power efficiency. HDDs remain highly cost effective for mass storage needs. For peak system performance, SSDs are the best choice to host the operating system and applications.
SSD average selling prices are falling, helping accelerate adoption. While HDDs will stay essential for affordable high capacity storage, expect SSDs to gain share in more systems thanks to improving price and performance.