• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

How on the X99 platform I got 16X/16X/4X + 4X M.2 PCI-E operation

Joined
Jun 30, 2008
Messages
330 (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.





 
Joined
Aug 18, 2017
Messages
340 (0.14/day)
Great to see that working! :clap:

Would love to see similar thing done on 115x platform with cpu's lanes.
That would require either socket modding, or cpu modding/soldering, because the bifurcation is controlled by hardware signals send to cpu pins/pads.

That might result in sick ITX configurations, like real SLI, or dGPU and two NVMe drives with no DMI bottleneck involved.

Supermicro provides probably almost every variant of riser/splitter, even ones with embedded PLX chip.
One has to be careful though, because some of them are non-standard, and dedicated to their motherboards only.
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
Well not sure about 115x. I looked into my Z270M mAtx bios and could not figure it out. Think the reason the Supermicro board worked out is because X99 is essentially a server based platform and the Supermicro tech support warned me it may not have worked but I am glad it did! Makes me wonder about if it be possible to run a raid off the slot while you still use the M.2 off of the PCH.
 
Joined
Sep 2, 2011
Messages
1,019 (0.22/day)
Location
Porto
System Name No name / Purple Haze
Processor Phenom II 1100T @ 3.8Ghz / Pentium 4 3.4 EE Gallatin @ 3.825Ghz
Motherboard MSI 970 Gaming/ Abit IC7-MAX3
Cooling CM Hyper 212X / Scythe Andy Samurai Master (CPU) - Modded Ati Silencer 5 rev. 2 (GPU)
Memory 8GB GEIL GB38GB2133C10ADC + 8GB G.Skill F3-14900CL9-4GBXL / 2x1GB Crucial Ballistix Tracer PC4000
Video Card(s) Asus R9 Fury X Strix (4096 SP's/1050 Mhz)/ PowerColor X850XT PE @ (600/1230) AGP + (HD3850 AGP)
Storage Samsung 250 GB / WD Caviar 160GB
Display(s) Benq XL2411T
Audio Device(s) motherboard / Creative Sound Blaster X-Fi XtremeGamer Fatal1ty Pro + Front panel
Power Supply Tagan BZ 900W / Corsair HX620w
Mouse Zowie AM
Keyboard Qpad MK-50
Software Windows 7 Pro 64Bit / Windows XP
Benchmark Scores 64CU Fury: http://www.3dmark.com/fs/11269229 / X850XT PE http://www.3dmark.com/3dm05/5532432
Proper work! Saluted!
 
Joined
Dec 6, 2005
Messages
10,881 (1.63/day)
Location
Manchester, NH
System Name Senile
Processor I7-4790K@4.8 GHz 24/7
Motherboard MSI Z97-G45 Gaming
Cooling Be Quiet Pure Rock Air
Memory 16GB 4x4 G.Skill CAS9 2133 Sniper
Video Card(s) GIGABYTE Vega 64
Storage Samsung EVO 500GB / 8 Different WDs / QNAP TS-253 8GB NAS with 2x10Tb WD Blue
Display(s) 34" LG 34CB88-P 21:9 Curved UltraWide QHD (3440*1440) *FREE_SYNC*
Case Rosewill
Audio Device(s) Onboard + HD HDMI
Power Supply Corsair HX750
Mouse Logitech G5
Keyboard Corsair Strafe RGB & G610 Orion Red
Software Win 10
Bifurcation... my new favorite word :)
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
Well as interesting as a challenge that is think i need to take a break. For one I don’t understand what processor signals are or even how to modify them. Table 6-7 in the datasheet details the signal configuration needed to set it at 8x 8x from 16x but I don’t understand if this is a binary bit needing to be set or what?

Thanks
 

Toothless

Tech, Games, and TPU!
Supporter
Joined
Mar 26, 2014
Messages
9,226 (2.52/day)
Location
Washington, USA
System Name Veral
Processor 5950x
Motherboard MSI MEG x570 Ace
Cooling Corsair H150i Elite
Memory 4x16GB G.Skill TridentZ
Video Card(s) Powercolor 7900XTX Red Devil
Storage Crucial P5 Plus 1TB, Samsung 980 1TB, Teamgroup MP34 4TB
Display(s) Acer Nitro XZ342CK Pbmiiphx + 2x AOC 2425W
Case Fractal Design Meshify Lite 2
Audio Device(s) Blue Yeti + SteelSeries Arctis 5 / Samsung HW-T550
Power Supply Corsair HX850
Mouse Corsair Nightsword
Keyboard Corsair K55
VR HMD HP Reverb G2
Software Windows 11 Professional
Benchmark Scores PEBCAK
I gotta ask which case is that to have your drive sit upright?
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
Having a little issue with my Plextor drive forgetting to set its self at pci-e gen 3 speeds after the computer has been shut down (warm - still powered). HWInfo will say its at a 2.5 GT/S link speed though still 4X lanes. The only fix I have found is to shut off the bifurcation mod and turn it on again, or uninstall the driver and reinstall the driver. Think it has to do with L0s + L1 Latency values. Also think its fixable through software though not sure how. Like the Plextor goes to sleep and not wake up out of a low power mode.

Thanks
 
Joined
Mar 24, 2010
Messages
5,047 (0.99/day)
Location
Iberian Peninsula
Check if there are reports of the Plextor doing it with all setups... ;)
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
You mean in other machines? Thinking about undoing the bifurcation and see what happens.
 
Joined
Nov 27, 2010
Messages
924 (0.19/day)
System Name future xeon II
Processor DUAL SOCKET xeon e5 2686 v3 , 36c/72t, hacked all cores @3.5ghz, TDP limit hacked
Motherboard asrock rack ep2c612 ws
Cooling case fans,liquid corsair h100iv2 x2
Memory 96 gb ddr4 2133mhz gskill+corsair
Video Card(s) 2x 1080 sc acx3 SLI, @STOCK
Storage Hp ex950 2tb nvme+ adata xpg sx8200 pro 1tb nvme+ sata ssd's+ spinners
Display(s) philips 40" bdm4065uc 4k @60
Case silverstone temjin tj07-b
Audio Device(s) sb Z
Power Supply corsair hx1200i
Mouse corsair m95 16 buttons
Keyboard microsoft internet keyboard pro
Software windows 10 x64 1903 ,enterprise
Benchmark Scores fire strike ultra- 10k time spy- 15k cpu z- 400/15000
That's pretty cool mod, nice. Thank god I dont have to deal with lanes ,as for two xeons= 80 lanes total, and each of the 7 pcie slots can be populated @x16 3.0.
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
Aren't you lucky. I'm beginning to think this is a problem with the drive.
 
Joined
Jun 30, 2008
Messages
330 (0.06/day)
Well I ran some more tests and it seems that a side effect of bifurcating the PCI-E 8X lane in two is that the Plextor occasionally sets itself to 2.5 GT/S mode. It doesn't happen when the bios hack is turned off and its not related to the riser cable. Interestingly enough the other NVME drive, the Samsung 950 Pro on the other end of the 4X switch, doesn't behave this way. So I think its something to do with the required latencies of the drive possibly the Payload side required. Not sure.
 

TristanDuboisOLG

New Member
Joined
Nov 14, 2018
Messages
1 (0.00/day)
Is it possible to get some documentation on how you did this? I'm part of the SFF community and not only are there a lot of people out there that could benefit from this, but I recently decided to make a SFF server and could really use it.
 

Agent-Orange

New Member
Joined
Dec 8, 2018
Messages
1 (0.00/day)
I would like to know, it that is also possible on an Asus Rampage 5 Extreme, to activate bifurcation on a modded bios.
 

Dev24670

New Member
Joined
Sep 11, 2023
Messages
1 (0.01/day)
ASUS Hyper M.2 x16 Card V1 w/4 drives On Asus X99 Deluxe II w/Intel 6850K 40 Lanes

This goes out to all the hard work executed by the following groups and members,
Win-Raid Forum
Techpowerup
Davidm71
Frogger
Lost_N_BIOS
Javen, THANK YOU!!!!!!!


I just need to revert my 16x5 slot back to Original setting
 
Last edited:

python1297

New Member
Joined
Feb 14, 2024
Messages
1 (0.02/day)
That's pretty cool mod, nice. Thank god I dont have to deal with lanes ,as for two xeons= 80 lanes total, and each of the 7 pcie slots can be populated @x16 3.0.
Pci bifurcation 80 lanes Hi E... I'm interested which motherboard you have used for the 7 pcie slots... pcie bifurcation research .... finding a motherboard with 2cpus is cool adding pcie bifurcation card is closest I found
 
Top