Generation rate or onboard memory

Hi,

im trying to generate digital signal with pxie 6544. I read in datasheet, that this device has onboard memory size 1Mbit/channel. In the other part of the datasheet, it says, maximum data rate per channel is SDR: 100Mbps or 400MB/s typical data streaming rates (I guess this rate means I can use all 32 channels with maximum rates 100MHz to generate signal).

I can use either 4byte or 2byte data for generation. But I dont think it would let me have bigger buffer size, right? 

Is there any ways I can generate signal somehow without using onboard memory size?