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What's the point in Lexar releasing superfast memory cards such as the 300x UDMA versions if it has to transfer onto your computer slower than a dead snail?
Lexar Professional UDMA dual slot: Specification
- High-speed file transfer
- Compact, portable design
- Reads UDMA CompactFlash, standard CF, SDHC, and SD cards
- Folds closed to protect card slots
- Two-year limited warranty
- USB 2.0 transfer
Direct memory access (DMA) is a process that's been used by computers for a few years now and allows hardware subsystems to access system memory for reading/writing independently from the CPU. This means that the running speed of the CPU isn't adversely affected so your computer won't slow down.
The term is a little different when referring to the Ultra DMA cards as it simply means that it's a faster download speed. In fact, Lexar CF cards boast 300x speeds which works out to around 45Mb/s transfer rate.
The transfer rate is measured against the speed that a CD player reads a CD which is around 0.15Mb/s. This means the 300x CF cards from Lexar are working 300x faster than a CD player.
Lexar Professional UDMA dual slot: In use
Installing the card reader into your computer is a simple plug and play operation as long as you have Windows XP. Indeed, Lexar recommend a computer with XP/Vista or OS 10.4.6 for Mac users.
So far the card reader only supports SD and CF but that's simply because Lexar have only made SD and CF cards UDMA (Ultra Direct Memory Access) enabled.
The reader is a small square box with a translucent plastic shield around the ports which are there to protect when in transit. A white rubber square is on the bottom to grip to surfaces when putting in or taking out a card.
Two small buttons either side of the front are pressed in and the main black compartment of the reader will spring up to allow access to the ports. This will then stay up in that position until depressed down again meaning it doesn't need additional support.
Lexar Professional UDMA dual slot: Performance
I tested the speed of a 300x speed Lexar CF card against a Sandisk Extreme II card transferring 486Mb of data to computer through a USB 2.0 port using a computer that has an AMD Athlon 64 X2 Dual core processor 4200 and 2Gb RAM.
The Lexar transferred the images in 20.25sec which works out at 24MB/s while the Sandisk was understandably slower at 43.11sec working out at 11.27Mb/s. Interesting results as the Lexar cards are supposed to run at 45Mb/s whereas in reality it's half the speed. There are a number of factors that need to be taken into consideration such as using USB 2.0 instead of Firewire and the performance of my computer but I don't think it would halve the result.
Lexar Professional UDMA dual slot: Verdict
I reviewed the Lexar 300x card when it was released and testing it through a card reader that wasn't UDMA enabled got a result of around 17Mb/s so using the UDMA card reader has certainly increased the transfer speed.
From a personal point of view as a reviewer, the limited card acceptability is an issue as you'd have to stick to CF or SD. Sony, Fujifilm and Olympus users would have a problem if their back up camera took any of those formats unless the camera had a dual slot so they could use SD or CF cards. Of course there aren't any of those formats with UDMA enabled technology so at the moment it isn't an issue.
Looking to the future, it may present a problem as the technology becomes more prevalent in cards and formats and it means additional expense.
It's a great card reader that certainly increases speed of transfer for today's "need it now" consumerism.
Lexar Professional UDMA dual slot: Plus points
Can be closed for protection
Advantageous with larger resolution cameras
Lexar Professional UDMA dual slot: Minus points
Difficult to benefit from the full speed
The Lexar Professional UDMA dual slot card reader costs around £30 and is available at Warehouse Express here: