960GB Class Performance Testing
The 960GB BX500 faces strong competition in this review. There are very few 1TB class DRAMless SSDs on the market at this time, but expect more in the second half of the year. The other drives in the charts today are some of our favorite SATA SSDs shipping today. Some of these drives are as close as $10 more than the DRAMless BX500, but have the additional chips that significantly increase random performance.
Sequential Read Performance
The lone QLC SSD, Samsung 860 QVO, stands out from the rest with slightly lower sequential read performance. The other drives all fall within a few megabytes per second through the queue depth (QD) range.
Sequential Write Performance
Sequential write performance is also very close with burst data between all the drives. This is due to the limitations of the SATA interface. NVMe SSDs using the four channels and the same flash are capable of delivering much higher performance.
Sustained Sequential Write Performance
The Samsung 860 Pro is the only drive without an SLC buffer. It uses 2-bit per cell flash. The other drives reply on writing to a programmed SLC cache that is often dynamic in size. The chart shows the best possible conditions, with the drives empty when we start and moving to 100% fill of the user area.
The 960GB BX500 shows a strong SLC area that is larger than many of the other drives. The three Samsung drives show faster 128KB block write speeds. The 860 EVO uses a larger buffer, but the 860 QVO drops faster than the BX500. Both the BX500 and the 860 QVO write large block size sequential data at less than 100 MB/s outside of the SLC buffer.
Random Read Performance
The MLC and TLC SSDs with DRAM read 4KB random data much faster than the BX500. The BX500 is significantly faster than the 860 QVO with QLC memory technology.
Random Write Performance
DRAMless SSD's weakest link is with random write performance. This is where the buffer for the table map really increases performance.
70% Read Sequential Performance
The 960GB BX500 has a flat performance curve with mixed sequential data. The performance in this area is lower than most of the other drives but it is predictable and consistent.
70% Read Random Performance
The low random write performance is burdensome. It takes the 70% read random workload down with it. This isn't just the low random writes alone. The increased latency disrupts the data pattern.
Although the performance looks low, and it is by SSD standards, the 960GB BX500 delivers nine times more performance in this test compared to the best consumer hard disk drives shipping today.