"To move data to or from a Lexar 1000X at the card's top speed, the host camera or card reader must be conversant with UDMA 7 as well. The D4 will be the first UDMA 7-capable Nikon camera, and while Canon's 1D Mark IV, 5D Mark II, 7D and 50D officially support it already (a firmware update is required), the support seems to have been limited to solving a slow-writing bug rather than capitalizing on UDMA 7's speed potential."
Here's my question. Can you still use one of these UDMA 7 cards in a non-UDMA 7 camera or card reader, and if so, how fast are they? Can a D800 or even a D300 use it, even if not at top speed?
The UDMA 7 1000x cards are supposed to be faster than the XQD cards. At the moment, I am needing another 32 gig card and am trying to figure out whether I'd buy the fast CF card or another XQD card. I'd probably lean towards the CF card if I knew if would still work in other cameras besides a D4. The last time I checked, the 1000x cards were more expensive than the XQD cards and would require me to buy one or two new UDMA 7 card readers.
When I take the time to write all of this down, buying more XQD cards seems to make the best use of my money, knowing I will be shooting mostly with a D4 for a long time. If I invested in a D800, speed of the card is not an issue and my old 600x CF cards would work fine.