Good post. I'd been having a bit of trouble figuring out how to phrase a search for these...
But in looking through the linked items, all I see is crap, crap, crap! These risers are obviously designed by people with zero knowledge of exactly what signals are being passed through those lines, and what sort of cabling arrangement needs to be done with them to "extend" them without signal degradation/errors. Every line is just passed through straight-across with no consideration of power, signal, crosstalk, etc...
PCIe is an internal interface, meaning it's not designed to go anywhere except where the mainboard had already positioned it. So in order for you to extend or move it, you should consider how to negate your "moving the slot", electrically - that is, how to make it appear to the computer like everything's normal. You set up twisted signal pairs, thicker/grouped power trunks, etc.
That may be why some risers are more expensive - they're actually
designed, not merely
manufactured. They won't give people undue amounts of headache ("OMG Y WONT MY MINER WORK!!1", "STUPAT PROGRAM CRASHES MY COMPUZER WHEN I OPEN IT!"), and they'll actually... you know...
work. BUT, on the other hand, there are likely to be places selling these risers for big "enterprise" setups that can get away with charging $300 for a 140gb hard drive (I'm an IT guy - shit like that flies like an F-16 around here, it's just sad). Those places are to be avoided like the devil. Honestly, I'd rather pay $15 for a piece-of-crap Chinese-designed straight-through-cabled riser, than $40 for an overpriced "server class" board and proper twisted cable. That's just exploitation right there
Of course, what I'm looking for is a board that splits a single 16x slot into 16 PCIe 1x slots that fit 16x cards (or maybe 4 4x slots, or 8 2x slots, etc). We already know that 16x cards work just happy at 1x, and that could really help a lot of people looking to use a cheap Atom-based MicroATX board as a PC, dramatically reducing power consumption and improving efficiency. All I seem to find are extenders for existing slots, but no "breakout" boards to split up existing slots into multiple slots (which is
entirely possible, from an electrical/logical point of view). I've only seen one setup:
http://www.amfeltec.com/products/x4pcie-splitter4.php... but it's not for sale, only bulk orders, and isn't exactly what I had in mind (x4 to 4x x1). Otherwise it'd be pretty nice.