Posted by: Ed Tittel
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This is the fourth entry in my recent “MyFaves” series: a collection of short and pointed appreciations for various hardware components of particular interest or value for Windows desktops, notebooks, and tablets. In this particular offering, I would like to recommend purchase and use of Secure Digital (SD) High Capacity (SDHC) or Extreme Capacity (SDXC) memory cards at sizes of 32, 64, or 128 GB for use in Windows notebooks, laptops, or tablets with suitable receptacles to accommodate those cards. These memory cards provide a terrific means to extend the storage of such units anywhere from modestly to significantly, especially on tablet or ultrabook systems that may have only 128 or 256 GB of SSD storage installed.
SDHC and SDXC cards come in many forms and in many sizes, but 32 GB or larger works best for extending portable notebook or tablet storage
[Image source: Tom's Hardware]
Until recently, I’ve routinely used 32 GB SDHC cards — which generally retail for around $20 these days — to extend and expand storage on my Lenovo, HP, and Dell notebooks, all of which I’ve converted from 300-500 GB conventional hard disks to SSDs in the 128 to 256 GB range (a mix of Intel and OCZ drives mostly, with a mixture of offerings from other vendors including Corsair and Samsung as well). Given tighter space on those machines as a result, a bit of added drop-in storage often proves very handy, especially on those systems where adding a second mSATA SSD is not an option.
But with the recent introduction of extreme capacity (SDXC) memory cards, available today in capacities up to 128 GB, 64 and 128 GB add-ons to compact portable systems are now achievable. Price ranges for these cards look something like this (abstracted from a total of 161 products available at Newegg.com):
- 32 GB: $28-30
- 64 GB: $37-150
- 128 GB: $85-180
The reason for the wide range of pricing for the higher-capacity models comes from different speed ratings for those respective memory cards. The most expensive offerings are generally labeled UHS Speed Class 1, followed in order by Class 10, and 400X speed ratings. According to the afore-cited Tom’s Hardware story (see link beneath image), maximum data transfer rates for these technologies are roughly as follows: 104 MB/sec for UHS Speed Class 1, 80 MB/sec for Class 10 (which actually guarantees a minimum 10 MB/sec rate), and 60 MB/sec for 400x devices. Ultimately, data rates as measured in their benchmarking tests show up at significantly lower values (here’s a sample table of combined streaming reads and writes, for example) with early UHS Speed Class 1 devices clocking in at between 13 and 20 MB/sec, and Class 10 at between 7 and 18 MB/sec).
To try this newer technology, I purchased a brand-new SanDisk Extreme Pro 64 GB SDXC card, having observed that the SanDisk Extreme memory card models generally come in at or near the top of all the comparative performance ratings. Here’s what CrystalDiskMark reported for that card in my Lenovo T520 notebook PC (Windows 7 Professional x64, i7-2640M, OCZ Vertex4 128GB SSD, 12 GB RAM):
Blazing fast results for the SanDisk 64 GB Extreme Pro memory card! As fast as my SSD, or faster…
Of course, I did have to pay through the nose for this memory card: it cost me $126.40 through a Newegg affiliate partner. The SanDisk Extreme Pro models are among the most expensive SDXC cards currently available, but they appear to offer a storage extension that is close to par with an SSD than most other memory cards do. As a true “storage extension” this is very desirable to me (this capability is primarily intended to serve on fast cameras where video recording or burst mode still photography puts pretty high demands on memory write bandwidth). Whether or not it’s sufficiently desirable to you to make the cost justifiable is between you and your checkbook!