NVME question about lanes

[1patriotofmany]

Hi There: I just installed a x8 pcie card that has two positions for m.2 cards. I'm running with one teamgroup m.2 card.  I installed the pcie card it in the 2nd x16 slot, because the x8 slot is right under a GTX3060. My question is I have the slot set for 4x4x4x4, can I make it 8x8 and get double the speed I'm getting or is the card limited to 4 lanes?   Blazing fast for me. Ran user benchmark and I'm getting 5-6 times what my sata ssd drive is doing.

[DGroves · Accepted solution]

most modern m.2 format ssd's have a controller chip on them that is hardwired to use four pci-e lanes as such changing the bifurcation in the bios from 4x4 to 8x8 on a quad pci-e ssd card will simply disable two of the four ssd's on that card

and if a dual m.2 pci-e card is changed from 4x4 to 8x8 no speed increase will happen as the ssd is hardwired to only use 4 pci-e lanes and  simply will not see/use more

[1patriotofmany]

Thanks I kinda figured, but wanted to make sure. Regards

[SDH]

The dual M.2 card I'm using in the Z440 and Z640 workstations is made by HP, the Z Turbo Drive Dual Pro. I've posted in detail about them here. There now are two versions and I've used both. In a Z440 no difference in performance between the two versions, but the v2 is rated by HP to support up to PCIe gen 4. The ZX40 and ZX G4 workstations both only have PCIe gen 3 slots. The gen 4 slot comes with the ZX G5 series.

In the Z440 you need to set the PCIe3 x8 slot bifurcation to x4x4 to use that slot with the ZTD DP card, and the lower PCIe3 x16 slot bifurcation needs to be manually set to x4x4x4x4 to use that dual M.2 card in that slot (even if you are only running 1 M.2 card in it). For a ZTD Quad Pro you'd also set it to that. That is a change from the default of "Auto" in BIOS. Of interest, in our Z4 G4s BIOS seems to have gotten a bit more mature... you can leave the slot setting to Auto and it will bifurcate automatically correctly for those HP cards. HP added bifurcation to the BIOS of the Z440 and the Z640 later. It was there earlier for the Z840, maybe from the beginning... DGroves would know.

I happen to like the v1 a bit better than the v2 version of the ZTD Dual Pro... it's heatsink is very sturdy vs delicate for the v2.

I understand that there are other non-HP dual M.2 cards that have internal plex chips... no experience with those.

[1patriotofmany]

Hey Dgroves, I saw in another thread you had linked to a pcie card that took care of bifurcation for non bifurcated motherboards like the Z420 and Z620.  Do you happen to know if that board also boot NVME drives in the 420 or 620?? The board ran around $200. Would be interesting to put in my 620.  I recently got a Z440 just for the bifurcation, very impressed at the read and write speed vs a SATA SSD.  I'm getting 5-6 times my SATA SSD.

[1patriotofmany]

SDH, I bought a cheap PCIE card $22 10Gtek card x8 and a 4TB TEAMGROUP NMVe, It works great, I disk cloned my boot drive with AOMEI software, boots and runs no problems from the nmve.  I wish they would make bigger nmve's than 4TB though, guess some technical thing limits them. Maybe make some bigger nmves that run on 8x8....