CPU-Z Vintage 1.03 is bugged and is showing a wrong memory frequency. If you disbelieve in the 303-MHz I also got a 301-MHz with 1.97.0
thnx to the high load of the newer versions it's impossible for now to validate any higher.
https://valid.x86.fr/4wxe0q
These are Corsair v5.3. Unknown stuff.
https://abload.de/image.php?img=corsair5.3nrko5.jpg
Some more results with these Chips:
https://www.hardwareluxx.de/community/threads/ddr1-ic-superpi-overclockingliste.1289659/
"unbekannte Chips"