To improve SSD performance, some models are equipped with an SLC cache. This acts like a buffer operating at high speed. A guy from TechpowerUp wanted to measure its impact on performance, and here are his findings. The tests were conducted on a 2TB Pichau Aldrin Pro SSD.
SLC cache: what impact on performance?
The tests revealed that this type of cache does help performance. When activated, it enables the SSD to achieve write speeds of 6.5 GB/s. However, this performance is only maintained for 691 GB and then drops off. Roughly speaking, when this cache is saturated, performance plummets. Deactivating this cache maintains a more stable, but lower, level of performance: 2.1 GB/s.
After carrying out a whole battery of synthetic tests, the SLC cache was found to support write speeds and reduce write latency. On the read side, its deactivation results in a slight loss of throughput.
However, during everyday use, such as loading a video game for example, there is no significant difference with or without cache. The same applies to tests such as 3DMark Storage. However, when transferring files, with the cache deactivated, there is inevitably a difference.
When it comes to energy efficiency, the SLC cache greatly improves the situation. When activated, the SSD offers an efficiency of 833 MB/s per watt compared to just 393 MB/s per watt otherwise. But in absolute terms, the SLC cache means a slight increase in power consumption: 7.39W with it compared with 5.38W without. On the other hand, there is no real difference in temperature with or without.