Hi Marc,

I have checked the MAP reports of both design and here is the difference: For the Element B:

AREA_GROUP AG_CU RANGE: SLICE_X6Y2:SLICE_X8Y1,SLICE_X5Y1:SLICE_X5Y1 COMPRESSION: 100 AREA GROUP Logic Utilization: Total Number of Slice Registers: 6 out of 14 42% Number used as Flip Flops: 2 Number used as Latches: 4 Logic Distribution: Number of occupied Slices: 7 out of

7 100% Number Slices used containing only related logic: 4 out of
7 57% Number Slices used containing unrelated logic: 3 out of
7 42% *See NOTES below Design Summary for an explanation of the effects of unrelated logic Total Number 4 input LUTs: 12 out of 14 85% Number used as logic: 12

For the element A:

AREA_GROUP AG_P00__CU RANGE: SLICE_X6Y2:SLICE_X8Y1,SLICE_X5Y1:SLICE_X5Y1 COMPRESSION: 100 AREA GROUP Logic Utilization: Total Number of Slice Registers: 6 out of 14 42% Number used as Flip Flops: 2 Number used as Latches: 4 Logic Distribution: Number of occupied Slices: 8 out of 7 114% (OVERMAPPED) Number Slices used containing only related logic: 4 out of

8 50% Number Slices used containing unrelated logic: 4 out of
8 50% *See NOTES below Design Summary for an explanation of the effects of unrelated logic Total Number 4 input LUTs: 13 out of 14 92% Number used as logic: 13

So now we can see that the amount of unrelated logic has increased!!

For the element C itself with the same constraints the data is: Logic Distribution: Number of occupied Slices: 7 out of

13,312 1% Number of Slices containing only related logic: 5 out of
7 71% Number of Slices containing unrelated logic: 2 out of
7 28%

I don't really see the the reason for appearing of the additional logic at the "A" level of hierarchy. The PLACE constrainis is set to CLOSED. :(

Alex