CREATE TABLE table_18823880_10 (l2_cache VARCHAR(255), release_date VARCHAR(255), part_number_s_ VARCHAR(255))
When by80607002529af is the part number and september 2009 is the release date what is the l2 cache?
    
SQL: SELECT l2_cache FROM table_18823880_10 WHERE release_date = "September 2009" AND part_number_s_ = "BY80607002529AF"