Hey guys, have a few questions regarding CF cards. I'm using a Sandisk UltraII 512Mb. I bought a 1Gb version about a month back and realise that the read/write speed is much slower than the 512 card I have. This is especially when I tried taking multi shots on my D70 in RAW format. I've tried using both card under similar conditions and the 1Gb card takes a longer time to write. Are there imitations in the market? Or are larger capacity cards naturally slower? I've compared both CF cards and packaging visually and I dun see any difference at all. Is there a way I can verify its authenticity?