ReadyBoost... from an SD card?

Hey all.

I've just been reading up on Vista's ReadyBoost feature and I wanted to get some opinions and information from everyone. First off, I was wondering whether or not there would be a noticeable difference in performance using ReadyBoost when I have two gigs of ram... from what I have read, it seems the more ram you have the less of an effect it has for you.

More importantly though, and more to the point, I was wondering if anyone had tried to use an SD card in a built in card reader as a readyboost drive. I am looking to do so because it's much more low profile and I don't have to worry about bumping it or using a valuable USB port. The issue is that after doing some speed tests, I have found that the access speeds for the built in card reader is quite a bit slower than the USB flash card.

I am using a 2GB SanDisk UltraII SD card and a 2GB Memorex flash drive for comparison.

The speed test results are as follows (values are rounded and averaged)

Now seeing as how the read times for the flash drive are almost double that of the SD card reader, (I am assuming that the bottleneck is the reader as the card is much faster with a USB reader) but the access times are almost exactly the same, how much of a difference do you all think this will make, and is it even worth using either one?

I apologize for such a long winded post, but I figured that some background information would be beneficial.
I look forward to hearing your opinions as, over the last few years, I have come to respect them greatly.

Dell XPS m1210
Windows Vista Home Premium
Intel Core2 T7400 2.16GHz
nVidia GeForce Go 7400
2GB RAM
160GB HD

I forgot to mention that is my previous post. I have already done so. I used the default 4096 cluster size.