If you choose to acquire another compact flash card suggest you use the read/write speed that matches your D300 raw file size.
For example, My Canon 5d creates 13 - 14 mb raw files on the compact flash card. The SanDisk Ultra II compact card has a 15mb/second rating. So a 14mb raw file can be written to the card in 1 second. Try matching or exceeding the CF cards rating with your cameras raw file size.
I think I got that correct.
Nikon D300 is a 12.3 megapixel dSLR. (Raw NEF 4288 x 2848 12.2 MPixel)
Forum Moderator for
EasyPano - Panoweaver