SanDisk Extreme II Solid State Drive SDSSDXP Review
By Olin Coles
Manufacturer: SanDisk Corporation (NASDAQ: SNDK)
Product Name: Extreme II Solid State Drive (SSD)
Model Number: SDSSDXP-240G-G25 (240GB Capacity)
UPC: 619659084080 EAN: 0619659084080
Price as tested: 120GB- $116.99 (Newegg|Amazon), 240GB- $224.99 (Newegg|Amazon), 480GB- $549.99 (Newegg|Amazon)
Full Disclosure: The product sample used in this article has been provided by Sandisk.
Solid State Drives: they’ve come so far in such a short amount of time. It was only a few years ago, or one computer upgrade for some, that your choices were a fast hard drive with not much storage space or a slow disk with lots of room. Back in those days, a memory upgrade was the easiest way to speed-up your system. Now we’ve got the SSD, a device that fetches programs faster than anything else we previously had available to us.
SanDisk may not have been the first name in the solid state drive business, but they’re among the best. Instead of offering a new product like some companies announce a flavor of the week, SanDisk ensures they’ve taken the time to reduce risk and failure to the lowest levels possible for their SSDs. As a result, they’re one of the few remaining brands that can offer consumers a five-year warranty that leads the entire industry.
In this article Benchmark Reviews tests the 240GB SanDisk Extreme II SSD, model SDSSDXP-240G-G25, against the leading competition. This slim 7mm solid state drive is advertised to reach 550 MB/s reads and 510 MB/s writes with its Marvell 88SS9187 SSD processor, while also reaching 95,000 IOPS for random reads. SanDisk then goes beyond simple transfer speeds and TRIM garbage collection by including proprietary nCache non-volatile write cache technology for its 19nm Toggle NAND Flash.
Solid State vs Hard Disk
Despite decades of design improvements, the hard disk drive (HDD) remains the slowest component of any personal computer system. Consider that modern desktop processors typically have a 1 ns response time (nanosecond = one billionth of one second), while system memory responds between 30-90 ns. Traditional hard disk technology utilizes spinning media, and even the fastest mechanical storage products still exhibit a 9 ms (9,000,000 ns) initial response time (millisecond = one thousandth of one second). In more relevant terms, the processor sends the command, but must wait for system memory to fetch data from the storage drive. This is why any computer system is only as fast as the slowest component in the data chain, which is usually the hard drive.
In a perfect world all of the components would operate at the same speed: system memory signals as quickly as the central processor, and the storage drive fetches data as fast as memory. With present-day technology this is an impossible task, so enthusiasts try to close the speed gaps between components as much as possible. Although system memory is up to 90x (9000%) slower than most processors, consider that the hard drive is an additional 1000x (100,000%) slower than memory. Essentially, these three components are as different in speed as crawling (HDD) is to walking (RAM) is to running (CPU).
Solid State Drive technology bridges the largest gap in these response times. The difference a SSD makes to operational response times and program speeds is dramatic, and takes the storage drive from a slow ‘crawling’ speed to a much faster ‘walking’ speed. Solid State Drive technology improves initial response times by more than 450x (45,000%) for applications and Operating System software, when compared to their mechanical HDD counterparts. The biggest mistake PC hardware enthusiasts make with regard to SSD technology is grading them based on bandwidth speed alone. File transfer speeds are important, but only so long as the operational I/O performance can sustain that bandwidth under load.
Bandwidth Speed vs Operational Performance
As we’ve explained in our SSD Benchmark Tests: SATA IDE vs AHCI Mode guide, Solid State Drive performance revolves around two dynamics: bandwidth speed (MB/s) and operational performance I/O per second (IOPS). These two metrics work together, but one may be more important than the other. Consider this analogy: bandwidth determines how much cargo a ship can transport in one voyage, and operational IOPS performance is how fast that ship moves. By understanding this and applying it to SSD storage, there is a clear importance set on each variable depending on the task at hand.
For casual users, especially those with laptop or desktop computers that have been upgraded to use an SSD, the naturally quick response time is enough to automatically improve the user experience. Bandwidth speed is important, but only to the extent that operational performance meets the minimum needs of the system. If an SSD has a very high bandwidth speed but a low operational performance, it will take longer to load applications and boot the computer into Windows than if the SSD offered a higher IOPS performance.