MaximumPC 2008 11

42 |MAMAMAXIMXIMXIMXIMUUUUMMPPPCC|NOV 08 |www.maximumpc.com

Breaking It Down

Before you make the move from a hard disk drive to a solid-state solution

you need to be aware of what you’ll gain and what you’ll give up

THE PROS

An SSD’s biggest boon is its performance

potential. Unlike hard drives, SSDs don’t

have to wait for a physical arm to move read

and write heads to specific points on a spin-

ning magnetic platter. Reading from flash

memory is a virtually instantaneous process,

giving SSDs the ability to reach faster ran-

dom read times and greater read throughput

than magnetic hard drives.

Another advantage to SSDs is their rela-

tively long life span. The NAND fl ash memory

cells found in SSDs can last for years beyond

the three- to fi ve-year life expectancy of a

magnetic hard drive. Because hard drives

include numerous moving parts, they are vul-

nerable to wear and tear over time, especially

if dropped or jostled.

An SSD can still break if you drop it, but as

a whole, the lack of moving parts makes the

category less prone to damage. If left unboth-

ered, a solid-state drive can last up to 60 years

longer than a hard drive in a similar desktop

environment. And as an added bonus, SSDs don’t

produce any noise and generate very little heat.

THE CONS

NAND fl ash is still a relatively expensive

technology, limiting the capacities of solid-state

drives and making for a high cost per gigabyte.

Some manufacturers have managed to lower

the cost of SSDs by using multi-level cell (MLC)

technology to cram more bits of data onto a

single memory cell. The problem is, MLC tech

incurs a performance hit over single-layer cell

(SLC) technology. The voltage complexities

involved in maintaining the multi-bit cells can

signifi cantly slow the speed of write operations.

Unless a manufacturer specifi es what

kind of fl ash memory powers its drives, you

won’t know whether you’re getting high-

performance SLC or low-performance MLC

fl ash. The price tag is the only distinguishing

factor outside of benchmarks: MLC drives

are among the cheapest SSD drives available

(typically half the price of SLC SSDs).

Manufacturers claim SSDs offer better

power savings than magnetic storage, but

that’s not always true. This greatly depends

on the construction of the drive: PATA- or

SATA-based SSD drives tend to draw more

power than typical hard drives.

Finally, SSDs can suff er from inferior ran-

dom write and sequential write times because

the data on an SSD is stored in kilobyte-size

blocks. Adding more data to a block is a time-

consuming process: The SSD copies the entire

contents of the block to RAM, changes the data

in the block, erases the original block of data

on the SSD, and writes the changed block back

to the SSD.

THE BENCHMARKS

We’re using our standard storage bench-

marking suite to compare seven solid state

drives against two leading hard drives:

Western Digital’s Velociraptor and Sam-

sung’s HD103UJ—the fastest hard drive

overall we’ve tested and the fastest terabyte

drive we’ve tested, respectively. This will

let us measure SSD performance against the

two extremes of performance and capacity.

Our h2benchw benchmark is a synthetic

test that measures a drive’s performance

over a large swath of read/write operations.

PCMark Vantage is our real-world bench-

mark, as it uses identical application traces

to simulate common drive operations caused

by normal desktop use. New to our bench-

mark testing is Adobe Premiere Pro. We

use the app to generate an uncompressed

AVI file straight onto a drive; the transfer

rate of such a large file can tell a lot about a

drive’s real-world ability to stand up to more

demanding tasks.

To see a comparison of all the drives’

scores, turn to page 50.

Expect to see upgrades in controllers and NAND fl ash push SSD

prices lower over time, but don’t hold your breath for either hard

drives or SSDs to ever oust the other from the marketplace.

According to Michael Yang, fl ash product marketing manager

for Samsung, NAND fl ash capacities will continue to grow at a

rate of 40 to 50 percent each year. This puts SSD development on

par with the 40 percent capacity growth touted by top hard drive

manufacturers.

A number of SSD manufacturers currently use PATA-to-SATA

bridges in their SSDs, but it’s expected that these manufactur-

ers will fully adopt the SATA 3Gb/s standard common to hard

drives within 12 months. You can also expect to see performance

upgrades to the actual NAND fl ash memory inside SSDs: In ad-

dition to block-size upgrades and an increase in SSD controller

channels, read-ahead and caching algorithms will improve the

drives’ write performance over the next fi ve years.

Single-layer cell (SLC) and multi-layer cell (MLC) technol-

ogy will continue to make up the fl ash cell foundations of solid-

state drives. But according to Yang, SSDs will start moving

away from the conventional form factors—1.8-inch, 2.5-inch,

and 3.5-inch drive sizes—established by the magnetic hard

drive market. This could bring forth SSDs of all shapes and

sizes, an appealing prospect for notebook vendors that want

more internal customization options.

LOOKING AHEAD

What the Future Holds for SSDs

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