O artigo da Wikipedia diz que, em alguns casos, é possível gerenciar o cache do SSHD a partir do host:
SSHD products operate in two primary modes:
Self-optimized mode In this mode of operation, the SSHD works independently from the host operating system or host device drives to make all decisions related to identifying data that will be stored in NAND flash memory. This mode results in a storage product that appears and operates to a host system exactly as a traditional hard drive would.
Host-optimized mode (or host-pinning mode) In this mode of operation, the SSHD enables an extended set of SATA commands defined in the Hybrid Information feature of the Serial ATA International Organization standards for the SATA interface. Using this feature, decisions about which data elements are placed in the NAND flash memory come from the host operating system, device drivers, host software or a combination of these host level components.
Um pouco de googling me diz que correções para fazer uso do recurso de informações híbridas de Revisão SerialATA 3.2 seção 13.20 foram submetidos para revisão, e esse suporte de fixação de host pode ser mesclado o mais cedo possível à versão 3.19.