Virtex5 vs Virtex6

Osama A. (aljarrah76) OP 2012-09-12 05:42 #2830955

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Hi there
I have synthesized the same code targeting both Virtex5 and Virtex6. I 
was expecting to get same number of LUTs because both of them have 6 
input LUTs. However number of LUTs for the case of Virtex5 was less than 
that of Virtex6 by approximately 30 LUTs. Is there any justification for 
this? Thanks

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Lothar M. (lkmiller) Moderator (Company: Titel) 2012-09-12 07:38 #2830985

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Osama Al-Khaleel wrote:
> However number of LUTs for the case of Virtex5 was less than
> that of Virtex6 by approximately 30 LUTs.
Compared to a total sum of how many LUTs? 50 or 5000?

The amount of logic is only half of the story. A different FPGA has 
different routing ressources and different routing strategies. And maybe 
the logic uses less slices and the routing uses more slices. But also 
the Translate and the P&R algorithms are different....

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user Guest 2012-09-13 20:59 #2833605

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The P&R algorithms are heuristic algorithms