buying extra CF card

I am a 40d owner. Today I went to costco and saw sandisk ultra II. I was wondering if I should get them or not. Would they hinder my camera from performing to maximum capability? Is there significant difference from sandisk extreme III (30mb/s), which i own right now. Btw i use my camera to take picture of anything from people to landscape.
thanks.

paul

Not really. I use ultra IIs all the time, and dont really have a problem. If your shooting sports alot or anything maxing out the buffer then maybe consider going to a ultra III

I shoot a 40d and have 4 of the Ultra II, 2gb cards. I have never had a "speed" related issue with them or any issue at all with them. The last one I bought was at Staples and I got it for $14.00 I believe.

Same here ... I use Ultra II 4 GB cards with my 40D. The extra speed of my Lexar 300X cards doesn't seem to have much effect in the 40D (they are MUCH faster in the 50D).

Maxdave

Unless you like to shoot on HS and long repeat bursts, there will be no difference, in use, between and Ultra II and an Extreme IV.

The difference will be noticeable when you transfer the images to your PC using a card reader.

I have a number of Transcend 133x/266x/300x cards, an Ultra II and recently bought a 16 gig Transcend 133x for when I travel. If I know I am going to be shooting bursts, such as sporting events, I use the 300x's, otherwise, the first card that I can grab.

Performance testing of various cards by Rob Galbraith. It's been my experience that you can fill a buffer even if you're not in high speed drive, especially if you shoot RAW or RAW+JPEG; it may take a little longer though. I've even filled the buffer of my 20D shooting at 3-6 sec. intervals over an extended period of time. Remember also that in-camera processing (Picture Styles, ISO settings, Highlight Tone priority if you have it, noise reduction) all affect your buffer capacity.

If you're in the US, SanDisk has rebates on ranging from $10-$60 (1-3 cards) with 4 GB Extreme IIIs and between $5-$30 on 4 GB Ultra IIs. At B&H prices, if you get 3 cards the Ultra II and Extreme III work out to the same cost after rebate and the Extreme III includes a file recovery program. If you buy 8 GB cards, the Extreme III is cheaper than the Ultra II after rebate.