Honored Contributor
Honored ContributorWhat is most likely happening is the tool is optimizing for memory block depth first vs width. So in your 2k deep solution, it's using the M4K in the 2kx2 configuration. and stitching them together to get your width. This probably gives you the best timing optimization vs area. (or ram utilization)
If the build is completing, I wouldn't worry about it. If your build is failing, try to optimize for area in the Quartus settings and see if that helps. If that fails, try to build your desired memory from smaller 512 x 9 blocks and stitch them together yourself. This really should be a fitting pass optimization, where it should try it both ways depending on the limiting factor (speed, vs ram block utilization). If it's failing with a can't fit, I would open a service request with Altera to request this feature. Regards Pete
