JDK-8272773 introduces the VM option `-XX:GCCardSizeInBytes` used to set a size of the area that a card table entry covers (the "card size") that is different from the previous fixed value of 512 bytes. Permissible values are now 128, 256, and 512 bytes for all platforms, and 1024 bytes for 64 bit platforms only. The default value remains 512 bytes.

The card size impacts the amount of work to be done when searching for references into an area that is to be evacuated (for example, young generation) during garbage collection. Smaller card sizes give more precise information about the location of these references, often leading to less work during garbage collection. At the same time, however, smaller card sizes can lead to more memory usage in storing this information. The increase in memory usage might result in slower performance of maintenance work during the garbage collection.