Time to import a French 7.12 core translation into the database.
Time recorded to execute _locale_import_read_po() in _locale_import_po() (gettext.inc). Measurement using timer_start() and timer_read().
Variable number of translations exist in the database before the import.

NO PATCH APPLIED
  0 existing translations: 14185.06 ms
10K existing translations: 16408.52 ms
20K existing translations: 16590.56 ms
40K existing translations: 16365.72 ms
80K existing translations: 16300.60 ms
                         
CRC32 PATCH              
  0 existing translations: 14493.45 ms
10K existing translations: 16598.72 ms
20K existing translations: 16160.89 ms
40K existing translations: 16784.29 ms
                         
MD5 PATCH                
  0 existing translations: 16415.88 ms
10K existing translations: 16842.65 ms
20K existing translations: 16922.74 ms
40K existing translations: 16739.26 ms
80K existing translations: 16626.70 ms