System build 2013: Using a budget "cache" SSD as an OS drive?

Having used a solid state drive on my 2010 build, there was no way that I would go back to having only standard hard disks for my 2013 build. After looking at various reviews and benchmarks, I decided that the primary SSD for this build would be a 128GB Samsung 840 Pro. At $130, it offers an amazing performance level that is on par with the larger SSDs that have more memory modules for the controller to work with. The Samsung unit is also double the capacity of my current SSD, which cost me $170 at the time. Although it is tempting to bemoan the cost of being an early adopter, it's actually quite impressive to see that 3 years later, I'm buying a faster, larger SSD for less money.

I digress. As I learned to live with the somewhat limited 60GB on my current SSD, I found that it was a bit of a lost cause to try to "manage" games and prune them aggressively upon completion, especially on a drive that was sharing the OS. Reinstalling, updating, and so on became a bit of a nightmare. Having an SSD with 0 bytes of space left would not make for a happy computer when it was time to apply an update, be it game or OS. World of Tanks managed this feat once or twice during a patch, which resulted in the dreaded "no more space" error message and left me scrambling to figure out how to clear up some space. Steam was too big to fit from the beginning. Now both Steam and Tanks have ended up residing on the slower hard disk. 128GB of space is an improvement, but it's still going to require some creative tweaking because my Steam folder alone weighs in at 144+ GB. Now, to be perfectly fair my Steam library has not yet been pruned, but factor in that I've got to install World of Tanks (~14 GB) and my OS (~16GB) and I'm looking at deleting 46GB of stuff just to have a drive that is totally full!

Using a dedicated OS drive is the solution I've come to, but what to use without being over-sized and over-budget? The SSD market as a whole has pretty much moved away from smaller size drives, which is disappointing. Enter the SanDisk Readycache drive, a 32GB drive intended as a cache drive to speed up traditional hard drives. The price is certainly right, at $39.99 it was the cheapest SSD out there that I could find. But how would it fare when I just format it, throw it into a computer, and install the OS directly onto it? The deck is certainly stacked against it, since it's smaller (and as a result has much fewer memory modules) and uses a less advanced controller that is apparently more suited for its intended use as a cache drive. I'm all for giving it a fair shot, so I picked one up. I figure if it can deliver even comparable performance to my current SSD for $40 I'll be happy.

I decided to momentarily install it in my 2010 rig to benchmark it versus my current SSD, and eliminate all other variables. Same system, same SATA controller. The results were actually pretty interesting.
(To be perfectly clear these were both on my motherboard's 3.0 GB/s SATA controller.)

First the baseline of my current Corsair Force Series 60GB:

Bear in mind that it might be showing some signs of age, but it's the best I can do with my current resources.

Now the SanDisk:

Interestingly enough, the sequential read is actually faster, at 136% of the Corsair's speed. Where it gets trounced, though, is the 4K random read, where it barely hits 31.5% of the read speed (but this is still much faster than the average traditional hard disk drive). Since booting Windows 7 is a mix of sequential and random reads, it's hard to call it in one direction or the other. I don't believe the SanDisk will boot faster than my Corsair, given how much the random read lags behind. What the real-world difference in performance will be remains to be seen. My initial impression based on the data and the fact that these numbers still handily outpace traditional drives is that the difference will likely be hard to notice, and on the order of a second or two.

The bottom line is that for the money, this drive looks like it's actually a pretty decent choice. It's not going to win any benchmarks for sure, but its selling point is its reasonably low cost.