MOS Technology SIDs. The left chip is a 6581. The right chip is an 8580. 'CSG' stands for Commodore Semiconductor Group. The numbers 3884 and 0692 are in WWYY form, i.e. the chips were produced week 38 of 1984 and week 06 of 1992. The last number is assumed to be a batch number.
Together with the VIC-II graphics chip, the SID was instrumental in making the C64 the best-selling home computer in history,[2] and is partly credited for initiating the demoscene.
^"6581 Sound Interface Device (SID) Chip Specifications". Commodore 64 Programmer's Reference Guide(PDF) (1 ed.). Wayne, Pennsylvania: Commodore Business Machines, Inc. 1982. p. 457. ISBN9780672220562. Archived(PDF) from the original on 2019-07-05. Retrieved 2019-07-05.