While Turbo Write is a feature that you can almost always take advantage of, Dynamic Thermal Guard is something that you hope to never use. Almost every SSD not specified for industrial applications has an operating range between 0 and 70 degrees Celsius. High temperatures can cause a number of issues with NAND, from lower write endurance to bit errors.
So, when Dynamic Thermal Guard picks up temperatures in excess of 70 degrees, it cuts back on write performance to reduce power consumption and, consequently, heat until the drive falls back into a safer thermal range. SSDs certainly aren't indestructible. They consume power, dissipate heat, and typically require airflow over their enclosures. This feature should help safeguard an SSD's sensitive components, even if the other parts in your PC are aggressively overclocked.
Finally, Samsung showed of the spoils of its 2012 acquisition of data caching company Nvelo. It's RAPID software-based feature allows the Samsung's SSDs to cache hot data in host memory to accelerate I/O. The performance improvements it showed off on-stage (and we later demonstrated on this page of our 840 EVO review) were outstanding.
The demo we saw in Seoul had read performance jump over 750 MB/s, while writes more than doubled to 1100 MB/s. Even though Windows already caches writes, RAPID takes this to another level entirely. It does come at a cost, though. RAPID uses up to 1 GB of host memory, though that number is dynamic and depends on the amount of RAM available. When asked about the possibility of power loss, David Lin, vice president of product management for RAPID, conceded that data could be compromised. He then tempered our concern somewhat by adding that RAPID responds to operating system flush commands, which are issued regularly.
RAPID is currently only enabled in Windows, but will be available for all 840-series drives once Samsung's Magician 4.2 software is released.
We're glad to see Samsung investing heavily in innovative ways to boost storage performance, and not just relying on its most obvious advantages over other companies. It's latest features aren't necessarily exclusive; however, when you combine them with a proprietary controller, the company's own flash, and planned firmware updates, it's clear to see that Samsung isn't resting on its laurels.