Well, the "SD: Sandisk, class 2" is actually a bit faster at both random and sequential reads than "SD: Sandisk Ultra, class 4", but sucks at random writes. Shows that if you mostly do reads (like, have a DOS gaming machine and the only writes are saves) a cheap card will do fine.
But I'm curious about the sequential write results - those are awfully close to one another. I suspect your OS just buffered all the data (so the testing program isn't actually doing it right). Also, the "200 bytes" category is kind of useless form device perspective, it's less than 1 full sector and will just get buffered the OS. So what is really measured here is the OS overhead and data copying rather than directly the card speed (but obviously that also has an impact). "200 bytes random write" is even more puzzling, some results are all over the place.
Cards, not just SDs but in gerneral, can have partitions or be just one "flat" volume wih a filesystem. The other option is like having just one partition but without partition table so you can't add more. But useful in many cases as you'd just want all of the card space for the FS anyway, plus partition tables have their limitations (DOS have size and count limits, GPT is very new and not well supported by small devices). I prefer the volume method - and for cards up to 512MB there really isn't any point in having PT unless you want DOS older than 5.0. It seems to work just fine with CF card on 386+ mobos. I realize that a big card has to be partitioned because FAT16 has 2GB limit but if someone's building a more modern machine with Windows NT4/95 or higher, you can use FAT32 or better yet NTFS. Or any of the ext flavours for Linux.
UPDATE: I take that back, I just checked and it seems DOS will create a partition table anyway (and then format it) during the installation process. It was so long ago I did that it somehow slipped my mind. So you can't have a single volume for DOS.
You can reformat the card, though I'm not sure if DOS FDISK can handle these sizes. There's always Linux. Windows has been dumbed down from version to version and nowdays you can't repartition the card (that's a software lockout for removable media). There are 3rd party tools though, like "FAT32 Format" for example. It doesn't partition though, only formats the already existing ones.