Modern UDMA CompactFlash Reader Benchmarks FireWire vs. USB 2.0

CompactFlash Reader Benchmarks		Sequential Data 4K blocks		Sequential Data 256K blocks		Random Data 4K blocks		Random Data 256K blocks
		Uncached Write	Uncached Read	Uncached Write	Uncached Read	Uncached Write	Uncached Read	Uncached Write	Uncached Read
FireWire 800 UDMA	ATP 300X Promax II UDMA CompactFlash 2GB	16.67	31.16	9.92	41.46	0.18	8.80	6.80	40.04
FireWire 800 UDMA	PQI 100X CompactFlash 2GB (PIO)	0.40	14.09	6.48	15.77	0.10	4.47	3.84	15.39

FireWire 400 UDMA	ATP 300X Promax II UDMA CompactFlash 2GB	15.09	27.56	7.77	37.54	0.18	8.53	5.93	37.08
FireWire 400 UDMA	PQI 100X CompactFlash 2GB (PIO)	0.40	14.10	5.47	15.76	0.10	4.50	3.67	15.50

USB 2.0 UDMA	ATP 300X Promax II UDMA CompactFlash 2GB	5.13	11.06	1.29	13.72	0.16	6.08	1.23	13.72
USB 2.0 UDMA	PQI 100X CompactFlash 2GB (PIO)	0.38	8.22	1.29	9.50	0.10	3.74	1.23	9.50

USB 2.0	ATP 300X Promax II UDMA CompactFlash 2GB	2.01	2.78	0.95	2.50	0.15	2.29	0.91	2.51
USB 2.0	PQI 100X CompactFlash 2GB (PIO)	0.34	2.73	0.95	2.51	0.09	1.94	0.90	2.51

These benchmarks demonstrate the wide gulf in speeds between high performance buses and lower performing buses when accessing data on UDMA enabled CompactFlash Cards. As with benchmarks comparing hard disk drives, FireWire consistently beats out USB 2.0 by significant margins for read and write speeds to mass storage devices. With recent UDMA CompactFlash reaching throughputs of Ultra ATA/133 (UDMA 6), choosing an appropriate CompactFlash reader to take advantage of such speeds is mission critical.

The point of high performance UDMA CompactFlash is speeding digital photography work-flows, which in the past were bottlenecked by digital media's read write speeds. While competing digital media cards employ slow serial busses, CompactFlash's parallel bus based off the PC Card standard have allowed for upward speed increases culminating with UDMA 6 CompactFlash cards like the Sandisk Extreme IV Ducati edition. Reading RAW DSLR files off CompactFlash as quickly as possible, especially in the field, is of paramount importance for professional photographers. For professional photographers, photojournalists, and serious amateur photographers USB 2.0 based readers aren't up to the task.

While USB 2.0's theoretical 480Mbp/s (60MBp/s) throughput should be sufficient for UDMA 4 CompactFlash, real throughput is significantly less. Top hard drive manufacturers typically cite USB 2.0's best speed at 33MB/s, or about half the speed of UDMA 4 CompactFlash, or 25% of UDMA 6 CompactFlash. There are myriad reasons for USB 2.0's 'real world' speeds including: CPU overhead from its master/slave arrangement, NRZI encoding, and inexpensive chipset implementations. The USB 2.0 UDMA reader used in the benchmarks above uses one of the latest USB chipsets from Genesys Logic. While a new generation of that chipset should soon be available, we don't foresee it providing throughput close to half of that of FireWire.

The above tests demonstrate both FireWire 800 and 400 readers are significantly faster for reading CompactFlash cards by orders of magnitude. When card to computer speed in crucial, always choose a FireWire based CompactFlash reader or a reader with a comparable bandwidth.

FireWire 800 CompactFlash Reader: PCM-CR-FW81ECF-02; CFFire800 Pro FireWire 800 to CompactFlash Drive Read-Writer; Blazing fast UDMA 6 and PIO 4 capable, CFFire800 is a professional's choice and the best option for high end CompactFlash Cards.

PCIe ExpressCard to CompactFlash: EXP34-ADP-CF2-02; CFExpressPro+ PCIe ExpressCard to CompactFlash Memory Card Adapter; The CFExpressPro+ PCIe provides portable performance with UDMA 6 capable PCIe ExpressCard for the most demanding applications.

Dual FW800 CompactFlash Readers: BNDL-FW8CF-01; UDMA Bundle two CFFire800 Pros, one FireRepeater 800, one 9-9 pin 1M Cable; Special bundle deal with FireWire 800 hub, cable and dual CFFire800 Pros allows use of two readers simultaneously off a single powered port.

USB 2.0 Multi-Card Read-Writer: PCM-CR-UEMUL03; MotionFlash32 USB 2.0 to 5 Slot Multi-Card Read-Writer; Uses the latest Genesys Logic chipset providing excellent read/write speeds for a USB based card reader. PIO Mode 6 CompactFlash and SD(HC) 2.0 Class 6 capable.