How Much Can The Code Be Compressed?

[Altera_Forum]

Hi Everybody, 

 I use ep3c25e144c8 cycloneIII fpga in my project and i use epcs16 for its configuration.  in the handbook of epcs16, it is written that epcs4 can be enough for EP3C25xx fpga when compression is enabled.  now i am confused..  is it enough for small amount of codes?  i mean, if i fully use 100% of 25K logic cells, can i compress it always to fit epcs4?  in jpeg compression, result file size depends on the picture information. and can my codes be large for epcs4? or can i use it without any doubts?  by the way, what is the difference between compressed and uncompressed code? why should i compress and why shouldn't?  thanks..

[Altera_Forum]

EPC3CS25 image fit's into EPCS4 if it can be compressed to below about 65 %. That's most likely the case with many designs, but can't be guaranteed. You have to decide based on your empirical design parameters. If you want to keep an option to use any possible image in later updates, you must provide EPCS16. Apart from this point, there's no advantage in using a larger memory or no compression. That's the whole story.