I'm going to start off by saying, this is a niche product. Even among us multiboxers.
I threw a link into some random post a while about, towards this product. Now I am making an actual thread so people can read about it/search for it.

ACard put together a Frankenstein of a "hard drive." They paired eight 240-pin DDR2 DIMM slots, with a 2400 mAh (around 4 hours) battery, and a forward accessible CF slot for backup purposes. According to the manufacturer: With the push of a button it takes ~20 minutes to back up 32GB to a CF card, and ~15 minutes to restore said backup.

RAM Drives are nothing new, but the last real commercial offering was the iRAM which had a limit of 4GB. This drive has a theoretical limit of 64GB, however there are no 8GB DIMMs listed on their compatibility list.

Now you may be asking yourself: “Self, why the hell would I care about this?”
Allow me to answer: Access Time.

WoW is largely affected by access times, due to the nature of having to load lots of very small files. As you are moving about the world (of warcraft), thousands of little texture/model/sound files are being loaded from your hard drive. Each time one of these is needed, the head must find the spot on the platter where the file resides and transmit it. This is why SSDs are much quicker at finding files than mechanical hard drives, SSDs have no moving parts.

Well RAM is even faster than SSDs. In the quest to read the most small files the quickest, the ANS-9010 takes the cake. Yes, I know what you are saying: “There is no cake.” Well that’s because the ANS-9010 took it.

I don’t expect you to believe me without tests to back up what I say, so without further ado I present TechReport.com’s Benchmarks.

The first test that pertains to WoW would be the IOMeter Webserver test. This test primarily consists of small reads, and well, look at the graph. TechReport IO Meter Test:
The ANS-9010 beats the Intel X-25 M (the fastest SSD on the market) by ~30%. (I eyeballed the graph, and pulled out a calculator, so don’t quote that percentage)

The second test that is significant is the HD Tach Random Access Time test. This is what we are really looking for. When the drive was setup in Raid0 it came in at .1ms response time. (So did the other SDDs test) When it was setup as a normal drive, without raid, it clocked a time of 0.0ms.

So, the bottom line is: This drive excels at handling small files.

The downsides are: You either have to backup the drive to CF each time you turn off your computer for more than 4 hours, or keep your computer turned on.
More CPU usage than a SDD.
The drive + the RAM will be about the same cost as an X-25 E drive.
However if you absolutely must have the best, this is the way to go.