> But the Transcend 8GB SDHC card is > only rated as an SDHC Class 2 device (which appears to only require > transfer speeds of 2MB/sec, from how I read the SDHC specifications). > Similarly the Toshiba 8GB SDHC card (the first one that claims to > meet the SDHC class 4 requirements of 4MB/sec) reports much higher > transfer rates in their press release - they claim 20MB/sec, which > is equivalent to 133x under the old SD speed rating system. > > Are you as confused as I am?
Indeed, its a weird 'upgarde' to the spec. I suppose the current situation is that the higher density cards are using the slower (but more densely packed) flash technologies. Still, why would they not spec out classes beyond 6 in the SDHC spec? Surely they'd assume 20mb/sec is only just round the corner; sandisk already do it in there SD extreme III's (well, about 17-18mb/sec in a K10D, but nominally 20mb) It also really makes me wonder why they do these silly incremental changes... "2G isn't enough? Lets revise the spec... but we'll only allow 32G, no one will ever need more than that...." why not just allow for umpteen terabytes and be done with it (at least for a few years :), if you're introducing a whole new (semi-incompatible) way of addressing the card. I notice though that the "Class" specification for SDHC also gaurantees the *write* speed to be a certain mb/sec, which makes a nice change from the dubious speed marking of previous SD cards. - Peter -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
