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AR# 41145

12.4/13.4/14.7 MAP - BRAM utilization summary in the MAP report


Slice Logic Utilization Used Available Utilization
Number of RAMB36E1/FIFO36E1s 206 264 78%
Number using RAMB36E1 only 206
Number using FIFO36E1 only 0
Number of RAMB18E1/FIFO18E1s 105 528 19%
Number using RAMB18E1 only 105
Number using FIFO18E1 only


What is the total BRAM utilization for this design?


There are not 264 RAMB36E1 and 528 RAMB18E1 on this particular Virtex-6 device as reported.

These 2 figures represent the total number of BRAM split into either 36K or 18K components.

As a results the total BRAM utilization is a combination of both of the above figures.


There are 206 RAMB36E1 used and 105 RAMB18E1 used.

A RAMB18E1 is half of a RAMB36E1 component, therefore 105 RAMB18E1 is the equivalent of 53 RAMB36E1 components. (105/2 + 1 for the extra)


As a results, total BRAM utilization is 206 + 53 = 259 or 98%

Adding the two values together will give a similar outcome of 97%. (This figure omits the extra 1 RAMB18E1)



AR# 41145
Date Created 03/09/2011
Last Updated 10/01/2014
Status Active
Type General Article
  • ISE Design Suite - 12.4
  • ISE Design Suite - 13
  • ISE Design Suite - 14