Upload & Sell: On
You may have uncovered the problem with failing to understand what Lars' test does and does not tell us.
It does not actually test what people (and camera companies) usually refer to as burst rate. In that context, "burst rate" refers to the number of images that the camera can capture per second before the buffer fills. What his test tells us is not that single thing. It is a sort of combination of a couple of things and a special case.
When you shoot in burst mode and shoot so many frames that the camera's memory buffer fills, the camera has to slow down and may now be limited in its speed by several other factors including the camera's write speed and the speed of the card.
I don't have actual numbers to quote, so I'll make some up that are useful for explaining the concept - think of them as illustrative rather than accurate specifications.
Let's say that the camera manufacturer quotes specs that describe a 8fps burst rate for up to 16 frames in some specific conditions - e.g. jpg or raw. If you press the shutter and hold it down, the camera can then record 16 frames in two seconds. This 8fps speed is pretty much (though perhaps not quite totally?) independent of card write speed. (Some other factors can make small differences in the actual burst rate, but I'll leave them out of this.)
What happens if you continue to hold down the shutter button in burst mode, past the point where the specified maximum number of frames has been captured at the 8fps rate? At this point the typical camera can no longer maintain that 8fps burst rate. It will continue to "burst," but often at a much slower speed that depends quite a bit on the camera's ability to write quickly to a card, which is a function of its own internal write speed and, if that is very fast, potentially of the card as well.
So the "30 second test" lumps together the very fast initial burst rate - which is not particularly affected by card write speed - and the post full buffer slower speed, which can be affected by factors including card speed.
If you are among the very small percentage of photographers who regularly continue to shoot in burst mode well beyond the buffer capacity of your camera, you might be interested in how many images the camera can capture in total during a long period of time. If that describes you, then I'll bet that the faster card - if you have a very fast camera, too - might be worth the extra cost.
If you are among the majority of photographers who don't shoot that way - e.g. don't generally "spray and pray" in 30 second "bursts" - then the value of the more expensive and faster cards may well be limited or even inconsequential - and the normal burst rate is going to be what it is as long as your card meets camera specs.
In the interest of clarity, I hope that helps.
One thing I've never understood is why does a card of higher denomination (say 128GB) have a higher burst rate than a smaller card (say 64GB) even though the cards are the same specification and speed?
Example from Lars data:
Transcend 64 GB UDMA 7 400x -----------123
Transcend 32 GB UDMA 7 400x ----------89
I don't understand how the capacity of the card can make such a difference in thru put. Certainly neither card approaches full on the test.
Anyone have insight on this?