How to Choose a Hard Drive
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1. Differences between HDD and SSD, their disadvantages and advantages
Considering the fact that SSDs have been dominating the memory market for many years now, and HDDs are gradually turning into artifacts of a forgotten civilization, it would be nice to start by reminding you of their fundamental differences, advantages, and disadvantages.
So, HDD(hard rim drive, or Winchester) is a traditional drive that uses magnetic plates coated with a thin layer of ferromagnetic material. These plates rotate at high speed (5400 or 7200 rpm), and on top them are reading heads that move along the surface of the plates, writing or reading data.
The main advantage of HDD is the low cost per gigabyte of memory, high maximum capacity and no wear when reading - data can be read almost infinitely without deterioration. However, HDD is significantly inferior to SSD in terms of operating speed, and mechanical parts make it vulnerable to physical damage.
SSD is a more modern solid-state drive with a fundamentally different approach to storing data. Instead of moving parts, it is equipped with flash memory (usually 3D TLC NAND) and a controller that manages the reading and writing processes. In fact, it is a whole microcomputer, inside which tiny memory chips are layered on top of each other, and the controller functions as a kind of central processor. At the same time, more expensive SSDs are often equipped with a DRAM buffer, duplicating the functions of RAM. However, let's not complicate things.
The key advantage of SSD is a much higher operating speed (in the case of M.2 models, it is even inconvenient to compare), compact dimensions and the absence of mechanical parts, due to which SSD does not make noise during operation and is not afraid of vibration. At the same time, the cost per 1 GB of SSD is higher, the maximum memory volumes are more modest (usually up to 4 - 8 TB), and the memory cells have a limited number of write cycles (from 300 to 3000). Although, the last factor is solved with the help of various wear leveling technologies and the use of reserve cells.
2. Form factors: 2.5", 3.5", external HDD
The 2.5” form factor is a compact and lightweight drive often used in laptops or for on-the-go storage. They are suitable for small amounts of data, but are rarely used in the context of servers and NAS systems due to their limited capacity and speed.
The 3.5” form factor is the standard for most desktop PCs, servers, and NAS. These drives offer large capacities (up to 24 TB), making them ideal for storing large amounts of data and handling intensive workloads, including video surveillance and archiving.
External HDDs are designed for data transfer or backup purposes. They can be useful for DVRs if regular deletion and saving of information is required, but for long-term operation in PC, server and NAS systems, their use is not so effective due to limitations in speed, durability and external connection.
In principle, it is quite difficult to give any precise advice on choosing the right type, since the form factor itself dictates the optimal usage scenarios. For example, not every server has the ability to connect an external HDD via USB, and 2.5” is not suitable for a PC, since most cases are equipped with 3.5-inch mounts.
3. Recording Types: Shingled (SMR) vs. Conventional (CMR)
In 2020, a scandal broke out: it turned out that Seagate and Western Digital had been selling HDDs with a cheaper and less reliable shingled recording type (SMR) for several years. We had a detailed article on this topic, so here we will briefly go over it.
CMR (Conventional Magnetic Recording) is a standard and more reliable data recording method that guarantees stable speed even during active write and read operations.
SMR (Shingled Magnetic Recording) is a recording method in which tracks are superimposed on each other, allowing for increased recording density. The emergence of SMR was caused by the need for a denser arrangement of plates in order to increase the maximum volume of HDD.
The problem is that with active use, SMR HDD is prone to significant speed drops, which are not always possible to return to normal by completely formatting the rim. Considering that the price of SMR and CMR HDD is almost the same, it is definitely better to choose CMR. The classic version provides stable flow Rate for any data operations, and this is especially important in the case of servers, NAS and video surveillance systems. And SMR disks are more suitable for systems with rare records and archival data storage.
4. Spindle speed (5400/7200 RPM) and cache memory
The spindle speed, expressed in revolutions per minute (RPM), affects the flow Rate of the hard drive. The higher the RPM value, the faster data can be written to or read from the rim. At the same time, a higher rotation speed is usually associated with increased noise and heat generation, which can affect the longevity of the hard drive.
For home PCs, the standard is 5400 and 7200 revolutions per minute. The first option is most often found in budget models, drives with a speed of 7200 provide higher flow Rate, but are also usually a little more expensive. For server rooms, where the continuity of the process is important, hard drives with 10 and 15 thousand revolutions per minute are more often purchased. Such hard drives provide minimal delays when writing and reading data, but their cost and cooling requirements are much higher.
It's also worth considering the presence of cache memory, which helps speed up write and read processes. Models with large cache sizes (32 MB or more) can provide significantly better flow Rate, especially when multitasking or working with large amounts of data.
5. HDD for video recorders and video surveillance systems
Unlike conventional hard drives, which have time to rest, HDDs for video surveillance systems have several specific requirements. The main one is the ability to work in conditions of constant recording and reading of data, since video surveillance systems often work around the clock, constantly recording large volumes of video files from cameras. Therefore, when choosing a hard drive for a video recording system, it is important to keep in mind several important factors:
- Durability and reliability. Many manufacturers produce special HDDs for video surveillance systems (for example, WD Purple, Seagate SkyHawk, Seagate Video, Toshiba S300), which support 24/7 operation, have a high write load, are optimized for multi-stream recording from cameras and easily withstand multiple write-erase cycles. Also, specialized HDDs for video recording are often more resistant to high temperatures, vibrations, voltage drops and emergency power outages than regular HDDs.
- Capacity. It is determined by the number of cameras, video resolution and archive storage period. For example, if one camera records Full HD video (1080p) at 4 Mbit, it will take up about 43 GB per day. For 10 cameras, you will need about 430 GB per day, and about 13 TB per month. To avoid making a mistake in calculating the required volume, many manufacturers have made convenient online calculators. The only thing we advise is to add a couple of TB on top if possible, since these are approximate estimates, and they often differ slightly from the actual figures.
- Speed and interface. Most DVRs and servers use SATA drives with 5400–7200 rpm. For large systems (20+ cameras), it is worth paying attention to models with a 64 MB cache and support for technologies that reduce delays when recording multiple streams. In addition to traditional SATA, they can use more specific connection methods such as SAS.
If the system requires reliability and durability, it is better to choose an HDD with support for special technologies WD AllFrame or Seagate ImagePerfect, which reduce frame loss during recording. In addition, specialized HDDs for video surveillance (WD Purple, Seagate SkyHawk) are optimized for operation in RAID, which reduces the risk of data loss and recording failures in multi-rim arrays.
6. HDD for servers and NAS
When choosing a HDD for server systems and home NAS, it is important to consider several key factors:
- Reliability and service life. Drives for NAS and servers are designed for 24/7 workload and high work intensity. Series like WD Red Pro, Seagate IronWolf Pro, Toshiba N300 have an increased service life (MTBF from 1 million hours) and are optimized for multi-rim configurations. Server HDDs (WD Gold, Seagate Exos, Toshiba MG) are designed for even more intensive workloads and have an MTBF of up to 2.5 million hours.
- Operating mode and load. HDD for NAS are optimized for storing and distributing data in RAID arrays, but are not designed for constant high load. Server hard drives, on the contrary, are designed for intensive work with databases, virtual machines and constant writing/reading.
- RAID support. Regular HDDs are not suitable for use in arrays due to the high probability of timeout errors (TLER, CCTL). NAS and server drives support these technologies, reducing the risk of RAID failure and data loss.
- Speed and interface. For home NAS, SATA 5400 – 7200 rpm models with a cache of 64 MB or more are sufficient. For highly loaded systems such as databases, HDDs with SAS 10K – 15K rpm or NVMe SSDs are often chosen, which can provide the highest level of flow Rate without compromising quality and reliability.
- Vibration and heat resistance. HDDs for NAS and servers are optimized for operation in limited space without overheating and harmful vibrations, which is an important factor for multi-rim systems.
- Volume. For home NAS, 4–12 TB per rim is usually sufficient, for servers and corporate systems, 18–24 TB and more models are chosen.
7. How to choose HDD for gamers
In all honesty, a hard drive for gaming in 2025 is not the best choice. SSD prices have long since leveled off, and the availability of gigabit Internet allows you to download and install most games in 20-30 minutes, and not half a day, as before. Plus, games load much faster on an SSD, and a fast solid-state drive with a PCI-E 4.0/5.0 interface can itself provide several additional frames per second due to faster buffering. Well, not to mention the fact that in the requirements of many AAA games of the current generation (Cyberpunk 2077, Starfield, Horizon Zero Dawn), an SSD is listed in the minimum requirements, since textures in the open world do not have time to load and the game will most likely slow down in busy objects or in dynamic scenes, and also twitch when turning the camera sharply.
In our opinion, using an HDD in a gaming system only makes sense if you don’t want to delete old games and plan to collect a whole museum collection in the future. In this case, it’s better to choose an HDD with a higher spindle speed (for example, 7200 rpm), which will provide faster loading compared to 5200 rpm. If your budget is limited or you want to install modern games without problems in the future, it’s better to choose an SSD. Or return to the once popular scheme, using an SSD for active games, and an HDD for storing games that you rarely play, but don’t want to uninstall.
8. What else to pay attention to
Is it worth overpaying?
An inexpensive HDD is enough to store movies, backups and other data that is rarely used. However, if the rim is to be used for high-load tasks (NAS, servers, video surveillance), then buying a more expensive HDD with an extended warranty and serious characteristics will be fully justified.
Checking the functionality
Although this point may seem strange, losing data from a server, NAS or video recording system can be a real problem. Fortunately, even when buying online, any normal store will provide a refund or replacement if the drive is found to be defective or does not meet the declared specifications.
After purchasing, it is worth spending a little time to inspect the HDD for physical damage and double-check the production date - old disks may have a reduced resource due to long-term storage in unsuitable conditions. After connecting, it is recommended to test the flow Rate and SMART parameters using the CrystalDiskInfo or HDDScan utilities, and, if necessary, check for bad blocks using HDD Regenerator.
9. Conclusion
As you can see, if in the household segment SSD drives easily and painlessly displace old hard drives from the market, there are enough cases in life when a classic HDD is a more convenient option for storing data. Considering the trends in the storage market, all the advice from this material will remain relevant for at least a couple of years. We hope that the advice will help you decide on the choice of a suitable HDD or reconsider your guidelines in favor of SSD.
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