Are larger capacity SDHC cards slower?

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Originally Posted by pnodrog

Keep up the good work Dave.

All microprocessor based systems have control, data and address buses either multiplexed or parallel. But who knows what is causing the inconsiderate behavour of your 32GB card.
Try disciplining it by giving it a good format every now and then.

Good luck

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Hah thanks :)

For these tests, I have been formatting each card in each new device I try them in, so as to start from a known point.

As the other 32GB does gives an improvement in the D5000 and this one doesn't seem bad in the S100, I think it is a P510 "feature".

Cheers,

Initial results for S100.

I have now analysed what happened when I had a quick play with the S100 - this wasn't as rigourously controlled as the P510 tests.
32GB C10 card; 6 images at 1 fps, followed by a steady 0.5 fps thereafter
8GB C2 card; 12 images at an average 1 fps, no measurable slow down from EXIF timestamps averaged
Throughput is continuous, unlike the P510, which explains the apparently bigger buffer when using the smaller card - it just doesn't fill because it is being emptied faster - something inapplicable to the P510.

So again, the smaller card seems to win, although in use, the difference is almost imperceptible.

I think I need to re-shoot this camera with all four cards (at least twice for averaging purposes) to draw a firm conclusion though. Ideally I need to shoot a clock or watch with a 1/10s sweep hand, but I don't have one.

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Originally Posted by Dave Humphries

If I shoot a burst of images, the buffer fills with 5 Large, Fine jpgs.
At a shutter speed of 1/2000s, this is all over in about 1 second, but the EXIF data assigns them consecutive timestamps one second apart. This means I can only be guided by the first timestamp in a sequence to determine buffer clearance (i.e. card write) speed - and then not numerically (insufficient resolution), only for comparison.

The results, using the four cards available today, showing the number of seconds between the first image in each of two sets of five, shot as close together as possible*, are;

32GB C10 card; 14.5 seconds
8GB C2 card; 7 seconds
4GB C2 card; 7.5 seconds
4GB C6 card; 6 seconds

the .5 second figures arose as I averaged two pairs (e.g. 14 on one and 15 on another = 14.5)

* You cannot shoot one burst and shoot second without, sometime in the buffer emptying process, lifting off the shutter button and re-pressing, this was the most consistent way to test.

Now I am intrigued as to whether the Canon S100, which although I don't use it for bursts, is also affected by the "larger memory space, longer write time", issue. So I may test that in a similar manner, mainly to discover whether the 32GB C10 I now have 'spare' is better off in that camera than the 4GB C6 I was using.

As they say; watch this space ...

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OK, here's what you may have been waiting for :)

I repeated the tests above with the newly arrived memory cards.

8GB C10 card; 7 seconds
4GB C10 cards 6.5 seconds

So a C10 card doesn't appear to give any advantage in buffer clearing time over a C6 in a P510.

Cheers,

Thats good that you now know which is the quickest option for P510, and you will have an abundance of spare memory cards now ;)

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Originally Posted by beckyhumphries

Thats good that you now know which is the quickest option for P510, and you will have an abundance of spare memory cards now ;)

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Yes, the 4GB C6 card I already had :D

Or one of the 8GB cards, twice the storage for a second longer writing, interesting that it seems to make no difference between C2 and C10 (in the P510) :(

Admittedly these weren't too scientifically applied tests, but I tried to be consistent.

The difference of a second may not be too reliable, so either the 4 or the 8 will do, but it is apparent there's a big difference going to 32GB though.