Max throughput of SOPC DMA?

If I do it like the example (silly me doing it slightly different..). I only get a throughput of 379 MB/s. Isn't there a way to make it go faster?

 
for 
(i = 0; i < number_of_transfers; i++) 
{
while ((RD_CSR_STATUS(MODULAR_SGDMA_ONCHIP_CSR_BASE) & CSR_DESCRIPTOR_BUFFER_FULL_MASK) != 0) {} // spin until there is room for another descriptor to be written to the SGDMA
control_bits = (i == (number_of_transfers-1))? DESCRIPTOR_CONTROL_TRANSFER_COMPLETE_IRQ_MASK : 0; 
construct_standard_mm_to_mm_descriptor (a_descriptor_ptr, (alt_u32 *)read_address, (alt_u32 *)write_address, length, control_bits);
if(write_standard_descriptor (MODULAR_SGDMA_ONCHIP_CSR_BASE, MODULAR_SGDMA_ONCHIP_DESCRIPTOR_SLAVE_BASE, a_descriptor_ptr) != 0)
{
printf("Failed to write descriptor 0x%lx to the descriptor SGDMA port.%c", i+1, TERMINAL_KILL_CHARACTER);
}