In the first place. The link shows the operating voltage 2.8 V, you put him out? The standard voltage for DDR1 modules typically 2.5 V.
Secondly. 400 MHz is twice the operating frequency. The link, again, is memory PC-3200, i.e. with a maximum bandwidth of 3200MB/s, which is achieved at a frequency of 200MHz, but because DDR data is transmitted not only front, but also from the decay clock pulse, compared to conventional SDRAM doubles the amount of transferred data, so marketers invented a new concept Ala the effective clock frequency, i.e. the equivalent of SDRAM. Here's to your memory real clock 200MHz and 400MHz effective. BIOS correctly identifies.