Check my SATA 2 math, please

My system has a SATA 2 controller. The docs say it will work with SATA 2, and its installed and beginning its caching process. My question is estimating “the hit” I take for SATA 2 versus SATA 3.

SATA 2, delivers 3 GB per second and SATA 3 at 6GB per second.

The specs say that the SSD cache delivers 480MB/s from it to the motherboard

If so 480MB/s * X 8 bits per byte = 3.8GB/sec

If that’s true, and my system can only move 3.0GB/s, I take a 20% hit on the advertised 4X improvment on 7200RPM 500GB SATA drive? .8 / 3.8 = 21%

If that’s true, I’ll be looking more in the neighborhood of 3x improvement? What does SanDisk see when testing the product?

This ssd should saturate the Sata 2 bus so your calculations should be pretty accurate. That said due to overheads you may get slightly slower than the full bus speed but this is typical. 

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Thank you. I ran quantative tests with Crystal Disk performance monitor and the results are pretty much as you describe. Qualitatively the computer performs better based on owning it a year before installing this unit. The jury is still out on the reboot times

Translation: I consider this a good solution for SATA 2 and I am satisfied with the results.