- Jun 30, 2008
- 275 (0.06/day)
As some of us X99 motherboard users know its only possible even with a 40 lane cpu to have 16X/16X/0 + 4X M.2 or 16X/16X/4X + M.2 PCH 2X operation. Just wanted to share how on my MSI Godlike X99 I was able to pull off 16X/16X/4X + 4X M.2 PCI-E mode. Was necessary to mod the bios to turn on Bifurcation mode of the last 8X lane pairs coming from the cpu. I had studied how on my motherboard MSI utilized switches to transfer the first half of the 8X PCI-E slot #5 to the M.2 onboard port. These switches were the same kind of switch used to transfer the other half of a 16X lane to the other 8X PCI-E Slot when more than two GPU's are being used. So it occurred to me that on the last PCI-E #5 slot the posterior half of that slot may still be active. So I set out to mod the bios to turn on bifurcation and purchased a Supermicro RSC-R2UU-2E4R 2U riser card and a 9cm riser extension cable. Hooked it up and right off the bat the OS initialized both drives at 4X PCI-E operation mode. Wrote a tutorial here.