Review: Samsung's 256GB SSD offers capacity, speed
But tests yield slower read speeds than Samsung claims
Senior Reporter, Computerworld |
I was deeply in techno-lust when I opened a UPS box the other day and pulled from it Samsung's new 256GB, SATA II laptop solid-state disk (SSD) drive -- stainless steel all around and oh so sleek. It sat in front of me and veritably screamed, "a quarter of a terabyte on flash memory." I didn't care that I didn't need that much storage capacity on my laptop. I wanted it anyway.
Samsung is marketing this 2.5-in, 256GB SSD as a drive with more than double the performance of its earlier 64GB and 128GB SSDs. It also claims this drive has the "highest overall performance in the personal computer industry." I tested that claim.
I put the drive up against Intel's X25-M SSD, which I consider the industry leader for SSDs when it comes to performance. Intel gets tremendous throughput on its SSD by interleaving NAND flash chips and using 10 parallel channels and optimized firmware, and it sips CPUs with just 2% utilization.
For my tests, I used a Dell Latitude D830 laptop with an Intel Core 2 Duo processor running Windows XP Professional SP2.
Like Intel's X25-M, Samsung's SSD is based on multilayer cell NAND flash memory, which means it packs two or more bits per cell versus more efficient, but lower-capacity single-layer cell memory, which only lays down one bit per cell. Samsung also has a multichannel interleaving chip architecture with eight parallel channels. And the company said it has upgraded this model's firmware and controller.
I also compared the Samsung SSD to a spinning hard disk drive: Western Digital's Velociraptor. While the Velociraptor comes in a 3.5-in. enclosure, which won't fit in most laptops, it's actually a 2.5-in. disk inside the larger enclosure. Either way, it's the fastest consumer-grade hard disk drive we've ever tested at Computerworld, so I thought it fitting to compare it with the newer technology of SSD.
From the start, Samsung's drive has an advantage in my mind over Intel's SSD in that it offers more than three times the capacity of the 80GB X25-M.
In our tests using Simpli Software's HD Tach, Intel's X25-M turned in I/O burst speeds of 256.7MB/sec. and an average read speed of 230.2MB/sec. Intel said its X25-M has a 2 million-hour mean time before failure (MTBF) rating, or 100,000 write cycles -- the same number of writes offered by more-expensive single-layer cell NAND memory. According to Brian Beard, SSD product manager for Samsung Semiconductor, the MTBF for the 256GB SSD drive is 1 million hours. Beard said that "if writing a large amount of data to the drive, say 20GB a day, our 256 SSD would last over 100 years."