I actually asked Nikon support essentially this same question but from a slightly different angle. I was considering getting an Eye-Fi card for the second slot and only saving basic JPEG to the card (so I can preview on my iPad), using the primary to save RAW. I was concerned about the speed differences effecting performance.

The response I got from Nikon was that the two slots operated completely independently of each other and writing lower res images to a slow card would not effect the performance of the other card. They recommended using the fastest Class 10 card available and implied that the camera can write faster than any card available today. I asked explicitly about the SanDisk Extreme SDHC Class 10 (30MB/s) 32GB card, and the reply indicated that it would support the card at full speed.

In the past few weeks I was working in porting a SD-Card driver for an embedded Linux device at work, and there are many factors you can blame when write speed is not what you want...

As mentioned before, the D7K does not need hyper speed cards :), the more faster cards will help you only in downloading the photos from your SD card.

There is another factor to take into account with SD cards, that is related to the SD card embedded controller, that may stop the write procedure in order to run some housekeeping procedures in balancing the usage of the card.. and this may hit you. The housekeeping may take almost a second, which may cause the write rate to drop below the requirements of the camera.

I think it does not matter whether the tester chose 15,25 or 50 images in his test procedure. The important part is that there was no difference in result whether using 30 MB/s, 45 MB/s or 95 MB/s rated cards. The limitation was the D7k's write speed.

Nikon have been rather pissy about inquiries about the write speed of the D7k since the very beginning. Their bad attitude about customers has done little to build brand loyalty or trust. They behaved like a bunch of knuckle heads and deserve to be treated as such.

The point of the linked article was that you get more 'bang for your buck' with a 30 or 45 MB/s rated card than with a 95 MB/s card. As the price drops the price premium for the 95 MB/s card will also so that you may be faced with a choice of buying cards that outperform your current camera so that they will be prepared for the next generation camera that has a better write speed.

The question no one seems to have any idea about at all is whether the write speed of the D7k is controlled by firmware (and hence capable of being uprated) or is hardware limited. My guess is that it is hardware limited, but I have no basis in fact for that other than my suspicion because of the poor way Nikon have treated customers about the entire affair.

Let's face it, 6 fps sound nice on paper, but is of limited utility when you can only do so (in RAW) for 10 exposures. After that the exposure rate drops to less than 2 fps until the buffer clears.

The 95 MB/s cards do not seem to be well distributed through the retail channels at this point. In a few months perhaps they will be and the prices will be more in line with the 45 MB/s cards.

Just to add more fun to this thread, I found at work, when using SD cards for recording images from a PillCam, that the write speed of a card is not the only parameter you need to look, also, the write speed may change as soon the card gets full, also it changes according to the age of the card (heavy used cards may take more time to write than brand new ones due to fragmentation or free clusters management.. (Every manufacturer does its NAND/NOR flash memory management differently, and not always published).

Oy...too much thinking going on 'round here.

http://en.wikipedia.org/wiki/Secure_Digital#Speed_Class_Rating

Class # x 1 MegaBYTE/sec (8 megaBITS/sec) = minimum sustained speed

:-)

I think the Sandisk class 6 cards are 24MB/sec, so it's more like 4MB/sec x the class number.

DaveO

As TaoTeJared commented at the beginning of this thread, it is enough to have a Class#6 card, faster cards will not speedup the camera processing/saving.. but it may speedup the download-to-your-computer speed. (e.g. using a faster card-reader for reading the SD card.)

About the class number and speed rating of SD (Secure Digital) cards can read here: http://en.wikipedia.org/wiki/Secure_Digital

Beware of the huge confusion between Mega bits per second or Mega Bytes per second, this changes the numbers by a factor of 8 (8bits=1Byte)

Hope it helps.

right now im using a platinum ii 100x 8gb card(it says 15mbs/s). so it would clear it faster? i read somewhere that cameras can only clear images at a certain speed no matter how fast the card. so would the extreme pro be wasted on the d3100?

Depending what your definition of "significantly" is and what you are using now, it would clear it faster.

how would the sandisk extreme pro be on the d3100? would if significantly reduce the time it takes to clear the buffer?

Drdobs said:
Cool wife.... :)

Yes she is, for over 20 years now! Just to tease her further, the battery grip showed up yesterday. Maybe the body will show up today?

PAG said:
After trying my D7000 and 300mm f/4 + TC1.4 for birds, my wife ordered them for herself. The lens, TC, NC filter, spare batteries, and new SD cards have all arrived, but she's on the edge of her seat waiting for the camera.

Cool wife.... :)

JorPet said:By the way, my two cards showed up today, camera should be here on Friday.

After trying my D7000 and 300mm f/4 + TC1.4 for birds, my wife ordered them for herself. The lens, TC, NC filter, spare batteries, and new SD cards have all arrived, but she's on the edge of her seat waiting for the camera.

TaoTeJared said:
CF cards are faster uploading to PCs than SD cards if they are in the same speed category - remember the speed class ratings are only the "must meet a minimum" speed.

That and the fact that the Extreme Pro CF is a 90MB/s card and the Extreme Pro SDHC is only 45MB/s, so the CF will always be faster at this level.

@PAG - I understood you were talking about in camera speeds and agree that the higher speed card probably is faster than the camera write speed, so you really don't get a benefit there. I still like the cards to download to my laptop as fast as possible, so the extra speed there should be nice. By the way, my two cards showed up today, camera should be here on Friday.

CF cards are faster uploading to PCs than SD cards if they are in the same speed category - remember the speed class ratings are only the "must meet a minimum" speed.

JorPet said:
Are you using a USB, USB II, or PCI interface to upload them to your PC?

I'm only talking about in camera performance. I didn't check PC download speed.

PAG said:
So I see a small improvement, but it's not a blistering difference by any stretch.

Are you using a USB, USB II, or PCI interface to upload them to your PC? I am thinking that if you are using a PCI interface that it should be a lot faster than the Extreme. Seems to be using my ExpressCard reader for CF and an Extreme Pro CF card.

I'm not sure what's up, but at the B&H site a 16GB Sandisk Extreme Pro (45MB/s) is $73.50 and the slower 16GB Sandisk Extreme (30MB/s) is $78.95.

teeboy said:
has anyone tried the new sandisk extreme pro in the d7000? if yes would you recommend this over the sandisk extreme? thanks.

I shoot a D7000 and I just got the Extreme Pro cards about 2 weeks ago. When at full speed burst, I get only one more frame on the Extreme Pro over the Extreme before the camera starts to slow down. The buffer seems to clear a few second faster.

So I see a small improvement, but it's not a blistering difference by any stretch.

B+H must have be updating some of it's site - I had to search Google to find it on there.

TaoTeJared said:
@studio460 - FYI - I just searched and they are for sale at B+H and everywhere else.

The 30Mb/sec. Extreme IIIs? Crap! I just bought the 20Mb/sec. last week! I don't know how I missed those. I was looking and looking all over B+H.

@studio460 - FYI - I just searched and they are for sale at B+H and everywhere else.

When I first bought my D7000, I bought a few SanDisk Extreme IIIs, rated at 30Mb/sec. I lost one, and needed more, but all I could find on the B+H site last week was SanDisk Extreme (no Roman numerals) at only 20Mb/sec. The Extreme IIIs, apparently, are no longer in current production. Anyone have a clue what exactly replaced the "IIIs" and why the datarate dropped 10Mb/sec. on the current "Extreme" product?

[The Extreme IIIs worked fine for both stills and 1080p24 video, by the way.]

I have both the sandisk extreme class 10 and the sandisk extreme pro UHS. It feels like the new UHS is a bit faster, but i have no hard figures to back that up.

Funny, just ordered two Sandisk Extreme Pro 8GB for the new D7000. They should all be here by Friday. I suspect that the Extreme is fast enough to handle the full write speed of the D7000, but I'm haven't been able to confirm that one way or another. I know the extra speed will be appreciated when I load them on my laptop as the slot is built into the UDMA controller so will probably read at the full speed of the card.

I use the CF Sandisk Extreme Pro in my D700 and it has been great. I have an express card bus reader for my laptop for that one and it flies when downloading.