*512MB. This is not an Apple innovation... I believe all SSDs have caches hanging off of the controller, used for both write and read. Flash memory is very much slower than DRAM when writing. This DRAM cache is why many SSDs have better burst performance than sustained write performance. Only the most high-end datacenter-oriented SSDs have backup power, typically supplied by supercapacitors rather than batteries though. I don't see any backup power on this Apple SSD.
