Is the AD/DA converter Cyclone 3 starter kit compatible

As I understood, SPI interface of DACs (AD5318) operates at clock rates up to 30MHz.

How much time is needed that DAC convert all 8 channels? As I understood, 8 channels x 16 cycles x (1/30 MHz) = 4.3 us... 16 cycles for each channel conversion or even more... Am I write?

As I work with signals 20-40 kHz (which is 25-50 us), I need to convert digital to analog signals in much shorter time (4.3 us is too much time)...

If all that is write, is there possibility to use some 8 channel DAC which converts all digital to analog signals simultaneously with SPI interface (which would last much less than 4.3 us) or to use 8 DACs which would be driven synchronously?

Thanks a lot!

Nikola