When you have heterogeneous SSDs, e.g. you mix PCIe 5.0, PCIe 4.0 and Thunderbolt interfaces, you can obtain a greater throughput by managing in software the distribution of data, than by using RAID0.
RAID0 works fine only when all the interfaces have the same speed.
If one SSD is twice faster than the other, in order to achieve maximal throughput, you must take care to place the data in such a way so that you will need to read twice more data from the twice faster SSD.
In general, you must distribute the data so that the amounts read from each SSD are proportional with the throughputs of the SSDs.
One could write a modified RAID0 device driver, which would use unequal stripes, with widths proportional with the SSD throughputs, but I am not aware of any such already existing RAID0 driver.
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When you have heterogeneous SSDs, e.g. you mix PCIe 5.0, PCIe 4.0 and Thunderbolt interfaces, you can obtain a greater throughput by managing in software the distribution of data, than by using RAID0.
RAID0 works fine only when all the interfaces have the same speed.
If one SSD is twice faster than the other, in order to achieve maximal throughput, you must take care to place the data in such a way so that you will need to read twice more data from the twice faster SSD.
In general, you must distribute the data so that the amounts read from each SSD are proportional with the throughputs of the SSDs.
One could write a modified RAID0 device driver, which would use unequal stripes, with widths proportional with the SSD throughputs, but I am not aware of any such already existing RAID0 driver.