Ok, just to confirm I am understanding your example correctly: Is the return value of spiRec an error count? Running the example as is I get no lines from SRAM0 rtn and screensful of SRAM1 rtn: . After making the change to ASAP in spiDmaRX I get two error lines in SRAM1 rtn: on average.
Edit: If I also make the change DMAC->DMAC_GCFG = DMAC_GCFG_ARB_CFG_FIXED; in spiBegin as well as ASAP in spiDmaRX I am getting no errors.
Update: Still no errors after 750 loops. 100 loops takes 228 seconds, which if I've calculated correctly would be a data rate of 4491Kbytes/s or 35.9 Mbits/s (looks about right)