Results: Performance Vs. Capacity
I really like HDTune Pro. It's a decent canned storage test full of helpful tools. The utility is great for evaluating hard drives, though a little less relevant to SSDs. The software's most prominent feature is its ability to write and read to the entire surface of a storage device. When you're testing rotating media, it's easy to observe speed dropping from the outer to inner tracks. That's just physics. With SSDs, the "surface" is the entire capacity, minus over-provisioning or spare area, and isn't directly mappable to a physical location.
Now, there are good reasons to use HDTune in SSD reviews. But there are notable limitations to be aware of as well. Most strikingly, HDTune writes in easily compressible zero-fill data, which isn't particularly useful for testing SandForce's technology. Also, I want more control over how the utility does its job. So, I created my own script-based version to do what I need.
Starting with a freshly erased drive, I write to the entire capacity and display my results as a percentage of the capacity. I separate the 256 and 512 GB SSDs into sequential chunks 1/200th of their total capacity. Then, each segment's average throughput is displayed as a data point representing 0.5% percent of the "surface".
This is what a 1 MB write across the entirety of the accessible LBA range looks like on the two X210s. With the write immediately preceded by the read, we get a sense of any peculiarities that SanDisk's drives might be trying to hide. We already knew what to expect based on early work with similar configurations, though: brutal and proficient speed at every position. Standard fare for most SSDs these days, with just a few exceptions.