investigate IMX8MQ_CLK_NOC
nxp's bsp has
/* increase NOC clock to achieve best DDR access performance */
clk_set_rate(clks[IMX8MQ_CLK_NOC], clk_get_rate(clks[IMX8MQ_SYS1_PLL_800M]));
which gives
noc 1 1 0 800000000 0 0 50000
while we have
noc 1 1 0 400000000 0 0 50000
Edited by Guido Gunther