I was thinking of buying a PCIe x1 based SATA Controller card to get more SATA 6Gb/s ports. Then an idea (based of logic) occurred to me -
PCIe 1.0 (the one inch slot) has a max theoretical data rate of 250 MB/s. that being said, even if I have a SATA 6Gb/s controller card and SATA 6Gb/s HDDs, wouldn't they run (at best) 250MB/s? Is there any reason (other than to charge more money) to have 6Gb/s capable controller cards if the PCIe port is limited to 250MB/s?
No. I was stating something that doesn't make sense on purpose because of the title of your post. Trying to be funny in a nerdy way and failing I guess.
The most you're going to get is 250MB/s because the slot is going to limit your bandwidth to 1 lane of PCIe 1.0. So if you want to use a SATA 2 card in the slot, it makes more sense. You'll almost get full theoretical bandwidth out of a single disk. If you add more disks to the card, they'll have to share the slot's bandwidth.