Thank you.Works great from the builds I've seen use it. Boloisbolo's build is my favourite:
On the [H] thread, I listed successful study cases with alternative risers from Supermicro, which are available on eBay.
@QinX explains all this on the first page of the [H] threadBirdofPrey said:Why aren't PLX based risers suitable?
How does clock buffer vary compared to a PLX chip?Three factors to the PCIe Bifurcation problem:
- Motherboard support.
Of released boards, there is either the ASRock Z170 Fatal1ty ITX (Bifurcation support out of the box), ASRock X99 ITX (Bifurcation support via special firmware on request), and ASRock Z87E-ITX (firmware not publicly available). IIRC, a Z270 board from Gigabyte was shown at CES with Bifurcation support listed in the specs.
- Riser support
The riser is required to contain a Clock Buffer chip. There are risers available that use a clock buffer chip, risers that use a PLX chip, and risers that contain neither. Only clock-buffered risers are suitable for use with PCIe Bifurcation.
- Software support
This is the remaining holdout, and little information is available due to so few people experimenting with DIY PCIe Bifurcation. Successes and failures have been reported both with AMD and Nvidia cards, on both Windows and Linux. If you are not using Crossfire or SLI, then compatibility seems pretty high, but if you are intending to use SLI/Crossfire then you will probably run into issues.
A PLX chip could be though of a little like a network switch for PCIe. It operates on every PCIe lane, making two discrete downstream devices appear to be a single device to the host, so the host does not necessarily need to support PCIe bifurcation.How does clock buffer vary compared to a PLX chip?
You did not ask me but let me share my own example please. based on the same forum and the knowledge collected here, I made this work.I came away from that thread understanding that -provided your chipset and motherboard had PCIe Bifurcation support - any passive splitter would work. So, that's not true, right? You need chipset/mobo support AND a splitter with a "clock buffer" chip? Any examples? Best one to get?
So why can't it be used? Does it mangle the signals?A PLX chip could be though of a little like a network switch for PCIe. It operates on every PCIe lane, making two discrete downstream devices appear to be a single device to the host, so the host does not necessarily need to support PCIe bifurcation.
The clock buffer chip's purpose is to ensure clock signals from the host are correctly passed to the two bifurcated ports (host is only designed to drive one client). It does nothing to the PCIe lanes themselves, so the host needs explicit support for PCIe bifurcation.
A PLX chip? In theory, the only problem with it is that PLX chips are rather expensive. In practice, having an extra device sitting in the middle of a high-speed bus can cause all sorts of odd issues. People sometimes have issues with multiple GPUs on motherboards where some PCIe slots are driven from PLX chips, and that is even after the whole assembly was designed that way from the start and has gone through validation with the motherboard manufacturer! Sticking a PLX chip in where it is not expected is in no way guaranteed to work.So why can't it be used? Does it mangle the signals?