CF vs. High Speed CF vs. SD

[Kiyoshi]

I have a SD card (signature) and I'm planning on getting a CF card next, but I want to know what the read speed differences are. When I run fairly high-quality video off the SD, my PDA drops lots of frames, even a few seconds at a time. Is the normal CF faster than an SD card or are the high speed ones the only CF cards faster than SD? And what speeds are there, I've really only seen 16x's and 40x's. But all those seem to be marketed to high-quality digicam users that want faster writes, not reads.

[Kiyoshi]

I have a SD card (signature) and I'm planning on getting a CF card next, but I want to know what the read speed differences are. When I run fairly high-quality video off the SD, my PDA drops lots of frames, even a few seconds at a time. Is the normal CF faster than an SD card or are the high speed ones the only CF cards faster than SD? And what speeds are there, I've really only seen 16x's and 40x's. But all those seem to be marketed to high-quality digicam users that want faster writes, not reads.

[SlimDady]

well eaxh "X" on a compact flash card is supposed to be 'x' = 150 KB/sec


So depending upon what speed you get that will change the performance

also different brands perform differently..




Thats all I can say about CF for ya,


I only use CF because thats what my camera uses, so I have a few cards already.

[Pony99CA]

Originally Posted by SlimDady

well eaxh "X" on a compact flash card is supposed to be 'x' = 150 KB/sec

That 150 KB/sec speed is true for CDs, but is it true for CF cards, too?

I know that a 4x DVD is running a lot faster than 600 KB/sec; the base speed (1X) is different for DVDs than for CDs. So I wonder if the base speed for CF cards is different than for CD drives, too.

Steve

[Pony99CA]

Originally Posted by Kiyoshi

I have a SD card (signature) and I'm planning on getting a CF card next, but I want to know what the read speed differences are. When I run fairly high-quality video off the SD, my PDA drops lots of frames, even a few seconds at a time. Is the normal CF faster than an SD card or are the high speed ones the only CF cards faster than SD?

I can't help with CF speeds, but I've heard that SD speeds get faster as the capacity increases. Here are the speeds I've seen listed:

• <= 128 MB -- 2 Mbps
• 256-512 MB -- 10 Mbps
• >= 1 GB -- 20 Mbps

Check out the "difference in memory cards?" and "Fastest Storage Media?" threads for some more information.

Steve

[Kati Compton]

I imagine the speed is also affected by the device itself - the interface with the memory card...

[Pony99CA]

Originally Posted by kati42

I imagine the speed is also affected by the device itself - the interface with the memory card...

Definitely. The iPAQ 3800 series, for example, implemented the SD interface using MMC-compatibility mode. This meant a one-bit interface instead of a four-bit interface.

That's why I don't bother trying to back my 3870 up on my SD card. Backing up to my CF card just now took 34:11 for a 41.7 MB file. The one time I tried to back up to SD took hours, if I recall correctly.

Steve

[davidspalding]

High speed CF cards are primarily for cameras. I don't think PDAs read and write so fast as to benefit from fast cards.

A digital camera site noted that standard Viking CF cards were as fast as the "high speed" cards from Sandisk. So I'd go with Lexar, Viking, Kingston for your memory. Leave the "highspeed" cards for cameras where write speed really is an issue (particularly where images are > 800 KB, whilst files on a PDA can be far smaller).

Just my 2¢.