Compare Between HDD , HHD , SSD , SSHD ?

HDD

Hard-disk drives have been the default storage component in desktop and laptop PCs for decades. As a result, the term "hard drive" is now the common descriptor for all storage hardware—the digital equivalent of "Q-Tip" or "Band-Aid." Although modern hard-disk drives are far more advanced and higher-performing than their counterparts from yesteryear, on many levels their basic underlying technology remains unchanged. All hard-disk drives consist of quickly rotating magnetic platters paired with read/write heads that travel over the platters’ surfaces to retrieve or record data.

The technology is mature, reliable, and relatively inexpensive compared with other storage options; most hard-disk drives can be had for only a few cents per gigabyte. Hard-disk drives are available in relatively high capacities too, with today’s largest drives storing up to4TB of data. Usually hard drives connect to a system via the ubiquitous SATA (Serial ATA) interface, and they don’t require any special software to work properly with current operating systems.

HHD

Hybrid hard drives blend HDD capacity with SSD speeds by placing traditional rotating platters and a small amount of high-speed flash memory on a single drive.

Hybrid storage products monitor the data being read from the hard drive, and cache the most frequently accessed bits to the high-speed NAND flash memory. The data stored on the NAND will change over time, but once the most frequently accessed bits of data are stored on the flash memory, they will be served from the flash, resulting in SSD-like performance for your most-used files.

Some of the advantages of hybrid storage products include cost, capacity, and manageability. Because only a relatively small solid-state volume is required to achieve significant performance gains, a large investment in a high-capacity SSD isn’t necessary. Hybrid drives tend to cost slightly more than traditional hard drives, but far less than solid-state drives. And because the cache volume is essentially hidden from the OS, users aren’t required to cherry-pick the data to store on the SSD to prevent it from filling up. The hybrid storage volume can be as big as the hard drive being used, and can serve as a standard hard drive. Boot times also see some improvement.

SSD

Solid-state hybrid drives are similar to hard drives. They usually connect to a system by way of the SATA interface (though PCI Express-based drives are also available for ultrahigh-performance applications), and they store files just as any other drive does. SSDs, however, eschew the magnetic platters and read/write heads of hard-disk drives in favor of nonvolatile NAND flash memory, so no mechanical parts or magnetic bits are involved.

By ditching the relative slothfulness of moving parts, solid-state drives deliver much better performance. They're the fastest storage option available. And not only can SSDs read and write data much faster than hard drives with most workloads, but they can also access the data much more quickly as well.

Whereas the fastest hard drives can read and write data at about200MB per second and access data in a few milliseconds, the fastest solid-state drives can achieve550-MBps (or higher) transfers that essentially saturate the SATA interface, and their typical access times are a fraction of a single millisecond. In a nutshell, SSDs make for a much snappier, much more responsive system, with lightning-fast boot times, application launch times, and file-transfer speeds.

SSHD

The tag line for SSHD lineup is "SSD Performance. HDD Capacity. Affordable Price". Essentially they are trying to say that these new drives will offer all the benefits of the two technologies without any real significant costs increases. If this was true, wouldn't all computer systems be using an SSHD instead of a traditional hard drive or a solid state drive?

The fact is that what these drives are is in essence a traditional hard drive with a small capacity solid state drive added to the drives controller to act as a sort of cache for frequently used files. It is not all that different from taking a standard hard drive to be the primary storage of a computer system and then adding a small solid state drive as a cache through a system like Intel's Smart Response Technology.

Let's break down the key criteria to help you decide which option is right for you.

Form factor

Without any moving parts, SSD products are the thinnest of the available storage options. They're especially good for thin and light PCs and complex, industrial designs. For standard notebooks, SSDs are available in5mm and7mm heights. By comparison, HDDs are available in standard7mm and9.5mm designs. SSHDs debuted at9mm, will ship at7mm soon, and5mm designs have been announced for shipment in2013.

Capacity

HDDs are the workhorses when it comes to sheer capacity and how much data can be stored. SSHD technology also offers maximum capacity points at affordable price points while SSDs are only affordable at lower capacities. High-capacity SSDs are extremely expensive.

Speed

SSDs provide peak performance for booting and high read/write performance to supporting computing that requires enhanced multitasking capabilities. On the other hand, an SSHD can provide near SSD performance for booting, launching, and loading data. HDDs usually provide ample performance for the majority of PC platforms shipping today.

Price

At a system level, low-capacity SSDs can be affordable in the32GB to64GB range. But high-capacity SSDs are very expensive, especially when measured by cost per gigabyte. HDDs provide the lowest cost per gigabyte. SSHDs provide a cost per gigabyte that's just slightly higher than HDDs.

Battery life

In general, storage will not impact battery life in a laptop computer by more than about10%. Processor power and LCD really run down the battery. However, SSD is the most power-efficient, and SSHD is a close second because it can spin down more frequently than an HDD.

Reliability

Failure rates on SSD, HDD, and SSHD technologies have very similar ratings. SSHD has benefits because it uses both the SSD and HDD portions more efficiently than if they were separate.

Durability

SSDs are viewed as more durable simply because of their solid state design. Without moving parts, they can withstand higher extremes of shock, drop, and temperature.

Summary

Thinking through all of these criteria may make upgrading laptop storage seem like a tough decision. But perhaps it all comes down to cost-effectiveness: How can you get maximum capacity that's nearly as fast as solid state but fits your wallet better?