Hello.
I would like some help with PCIE bifurcation support on my GA-X79-UD5.
Im using BIOS version <a href="https://www.mediafire.com/file/e62qpyhpih7iqv5/X79UD5.14e.zip/file" target="_blank">F14e </a>, which I got from the TT forum. I added nvme support from the guide posted here and it works great. I can also post my own modded BIOS and any additional information if needed.<br /><br />So far I have only one Samsung 256GB nvme SSD in the x8 PCIe 2 slot addon card (2x x4). I ordered 2x 1TB, but Im figuring Ill need this modification in order to use the addon card properly. Do I?<br /><br />First PCIE x16 slot has the graphic card, 2nd x16 PCIE slot has the addon card and 3rd slot is vacant at the moment.<br /><br />Ive searched through the whole BIOS but I cant find any options with this description. Maybe its in some hidden menu but I dont know how to access it. <br /><br />Is this possible on gigabyte x79 like it is on the ASUS x79s and has anyone made it work?
Greetings!
@pawx - What NVME adapter card do you have? I didn’t think there was any adapter slots for what you intended that only have two slots, sounds like you may have picked up a cheap adapter that only has NVME + SATA M2 slot.
Bifurcation can be done on this board, but only via AMIBCP or manual edit of the same as AMIBCP would do in AMITSE/SetupData + NVRAM.
The settings are located in the hidden debug menu under “System Information” and you can only set one slot, then test, then set the other slot, then test etc until you find which setting = which slot on your board, they are not labelled in a way that directly corresponds to slot normally.
One slot will only be able to do 4x4x, but the others can do 4x4x4x4x + all the rest of the combos below that.
@Lost_N_BIOS Thanks for the reply
This is the addon card I have Fujitsu m.2 carrier
The SSD is in the slot closest to the motherboard.
Thia motherboard has 3 PCIE x16 slots. 1st and 2nd are full x16 slots, the last one is only x8 electrically. I’m guessing this is the difference.
I try the SSD in the other slot when I get home and see if it boots.
Greetings
Thanks, it looks correct then, and reviews say it works. Well at least one person does anyway, and he mentioned bifurcation too, so he knows what he’s talking about and possibly the other reviewer did not)
Any of the three slots will work, but you need bifurcation enabled first. I will make you three BIOS now, with 4x4x set on each slot once for each BIOS.
You will have to test all three BIOS, and see which one makes the card work 4x4x in the slot you want (Then let me know, so I can make note of it for others in this BIOS folder)
* Edit @pawx - Here, please test each one and let me know which changes the third slot you wanted. if none change, let me know and I will make additional edit to setup, in case it’s pulling setting from there instead of NVRAM or AMITSE/SetupData
http://s000.tinyupload.com/index.php?fil…785782265715263
Flash via QFlash
@Lost_N_BIOS Hello. Ive finished my testing.<br /><br />First of all I have apparently misremembered how the PCIEx16 slots are on this motherboard. They go like this:<br /><br />Slot 1 - PCIEx16_1<br />Slot 2 - PCIEx8 (and is only x8 electrical too)<br />Slot 3 - PCIEx16_2<br /><br />There is also a PCIEx1_1 between slot 1 & 2 and PCIEx1_2 between slot 2 & 3. I dont know how important this is, but I just wanted to make sure the correct info is here. Here is the the board view.
Now for the testing. I did not receive my new SSDs yet because delivery is slow.
I tested the BIOS by putting the one nvme SSD I have in both 1st & 2nd slot of the addon card to see if it boots or not. The 1st slot of the addon card is the one closest to the motherboard and goes electrically to the first half (4x), 2nd slot goes in the second half (4x) of the 8x PCIE addon card.
I hope this is enough to see if it works or Im just going to have to wait for my mail to arrive and test with both drives in the slots.<br /><br />Here are the results:<br /><br />BIOS: X79UD5IOU14x4x.14e<br />PCIEx8 - MB slot 2<br />addon card slot 1: works / boots<br />addon card slot 2: works<br />PCIEx16_2 - MB slot 3<br />addon card slot 1: works<br />addon card slot 2: does not work / does not boot<br /><br />BIOS: X79UD5NVMEIOU28x4x4x.14e<br />PCIEx8 - MB slot 2<br />addon card slot 1: works<br />addon card slot 2: works<br />PCIEx16_2 - MB slot 3<br />addon card slot 1: works<br />addon card slot 2: does not work<br /><br />BIOS: X79UD5NVMEIOU38x4x4x.14e<br />PCIEx8 - MB slot 2<br />addon card slot 1: works<br />addon card slot 2: works<br />PCIEx16_2 - MB slot 3<br />addon card slot 1: works<br />addon card slot 2: does not work<br /><br />Im guessing if it works in both slots that would mean bifurcation works? If you need any more information or a different kind of test let me know.
Greetings!
@pawx - Bifurcation deals with a single slot only, so your thoughts and results above don’t help figure anything out.
Please add stock result from same test to above, then maybe it could tell us something, but only maybe about which BIOS I sent you is affecting which slot possibly (but none of this helps w/ bifurcation info without two NVME in a single adapter card)
You’ll have to wait until you have more than one NVME on a single adapter card to test anything here, unless you can see the expanded BUS in HWINFO64 (check this with each BIOS, with something in all slots one by one vs stock BIOS and what you see with it in same test scenarios)
Also, when you do get your other NVME, please read your manual for your adapter card if possible, some cards you have to use certain slots on the adapter for certain amount of NVME’s
When is your other NVME due in?
@Lost_N_BIOS Thanks for the reply. Im going to wait for the drives to arrive, should be tomorrow. <br /><br />I will use the one I have + one of the new ones to check if they both show up without losing time and installing windows again on the new ones.<br /><br />Also one other thing Id like to know. I`m not testing the 1st PCIEx16 slot since it sits the graphic card. Does bifurcation affect how a graphic card would work?
Greetings.
@pawx - You’re welcome! Yes, best to have both drives before we do any actual testing. It would be helpful though, if you flash back to stock BIOS and redo the tests you did above, so we have stock comparison with those results too.
Yes, graphics card would have it’s lane width cut if/when that slot is bifurcated (ie so, with one of the test BIOS I sent you, probably).
Check lane width for that card with GPU-z, with each of the BIOS I sent, once you see x8 or x4 width for the graphics then you know that BIOS affects that slot and we can rule that one out from future test edits.
Check “Bus Interface” two boxes down, under brand logo, it will show PCIE 2.0 x16 normally, and then if settings are bifurcating that slot it would show x8 or x4 instead, depending on BIOS setting
https://www.techpowerup.com/download/techpowerup-gpu-z/
@Lost_N_BIOS - Hey. Ive received the drives and did further testing.<br /><br />Here is the stock BIOS (with nvme) test result with 1 SSD installed:<br />PCIEx8 - MB slot 2<br />addon card slot 1: works<br />addon card slot 2: works<br />PCIEx16_2 - MB slot 3<br />addon card slot 1: works<br />addon card slot 2: does not work<br /><br />After this I tested all 4 BIOS for how they affect the 1st PCIEx16_1 lane and the BUS interface speed:<br /><br />Stock X79UD5.f14w works in x16 mode<br /><br />X79UD5NVMEIOU14x4x works in x16 mode<br /><br />X79UD5NVMEIOU28x4x4x works in 4x mode<br /><br />X79UD5NVMEIOU38x4x4x works in 16x mode<br /><br />Then I installed the new nvme SSD into the 2nd slot of the PCIEx8 addon card and tested the 3 BIOS - I left out X79UD5NVMEIOU28x4x4x since PCIEx16_1 only worked at 4x speed.<br /><br />Here are the results for 2x SSD:<br /><br />X79UD5 with NVME stock<br />PCIEx8 - MB slot 2<br />addon card slot 1: works<br />addon card slot 2: does not work<br />PCIEx16 - MB slot 3<br />addon card slot 1: works<br />addon card slot 2: does not work<br /><br /><br />X79UD5NVMEIOU14x4x<br />PCIEx8 - MB slot 2<br />addon card slot 1 : drive works/shows<br />addon card slot 2: <b>drive works/ shows</b><br />PCIEx16_2 - MB slot 3<br />addon card slot 1: drive works/shows<br />addon card slot 2: doesntt work/show
X79UD5NVMEIOU38x4x4x
PCIEx8 - MB slot 2
addon card slot 1: works
addon card slot 2: does not work
PCIEx16 - MB slot 3
addon card slot 1: works
addon card slot 2: does not work
Im guessing that X79UD5NVMEIOU14x4x is the winner here :). I works in the PCIEx8 slot and it shows the other SSD in the device manager & disk management. <br /><br />Do you need to make any further modifications or is this BIOS safe to use now?<br /><br /><small>Another question I have is. At the moment I dont have anything in the 3rd MB slot and it is PCIEx16 slot but I might get something in the future. Will it work at x16 BUS speed or will it be split with this BIOS?
I can`t put a GPU inside to test it because there is not enough space unless I take the motherboard out.
Edit: Nevermind, I managed to stuff it in the slot and it works @x16.
Greetings!
@pawx - Each BIOS I sent you ONLY bifurcates one slot, so whichever works for you in the slot you want, the other slots will not be affected or changed.
So, which BIOS works for which slot, that you wanted to use?
@Lost_N_BIOS Hey. Im sorry, I didnt completely understand how it worked because I had a brain fart. I had this image in my head from some other BIOS settings on other boards and I got confused.
Just to be sure I tested BIOS X79UD5NVMEIOU28x4x4x again with the GPU in the PCIEx16_2 slot (3rd MB slot) just to see if it would work with 2 NVME drives in the PCIEx16_1 (1st MB slot) since in was the one showing BUS speed of x4 only. It does not work.
Final results:
The only BIOS that works for me and shows both nvme drives is "X79UD5NVMEIOU14x4x" and it only works in the PCIEx8 slot which is the 2nd MB slot. This works for me.
All other BIOS do not work with my setup using Fujitsu m.2 carrier PCIEx8 addon card. Maybe its because they are full x16 lanes? I dont know. I`ve switched the GPU around and it does not show in device manager.
Thank you so much 
@pawx - Yes, I only made one slot change per BIOS. So if you need some other slot to have same changes, we need to make further changes to find which one would affect the slot you want to use.
Full x16 lanes on the card does not matter, so it’s not due to that. It’s may be possible, that one of the 8x4x4x would work on the other slots too, but only if I set 4x4x8x instead. Do you want to test that first, this would only be two BIOS to test?
If yes, might as well, here is those BIOS - http://s000.tinyupload.com/index.php?fil…754924490834204
Please let me know which IOU# works for which slot now, so I can make a note of this for other users in future, from your above test result we know IOU1 = second PCIE slot
If these also do not work, we can try again but with 8x8x or 4x4x4x4x, one of these will get it for all slots 
So if above do not work for slot 3 also, lets carry on testing until we find out which does work, if you don’t mind, thanks!
@Lost_N_BIOS Hey. Ive tested the new BIOS. It took me a while since I had some trouble cloning the old SSD onto the newer one.<br /><br />Here are the results:<br /><br />BIOS IOU2 = works in the first PCIE slot, both drives show.<br /><br />BIOS IOU3 does not work in the first or third PCIE slot. I did not check the second one.<br /><br />It would be nice to have an option for the 4x4x4x4x for anyone trying to use something like "HYPER M.2 X16 CARD V2", then again it is kind of a waste since you cant put them in a RAID setup. Also I have no way of testing more than 2 drives at the same time.
I˙m willing to test more, I just hope my MB BIOS does not get Vietnam flashbacks 
Greetings
@Lost_N_BIOS
Hello.
Youve helped me a lot in the past and everything works great.<br /><br />Ive upgraded my GPU and it has a 3 slot cooling solution and I can`t use my middle PCIE slot anymore. This is the one which had my SSDs on a m.2 carrier.
Could you please take a look and see if you can enable bifurcation on the last motherboard slot (PCIEx16 - MB slot 3)?
I would greatly appreciate if you can make this work.
edit: BIOS test results so far
X79UD5NVMEIOU14x4x - works in PCIEx8 - MB slot 2
X79UD5NVMEIOU24x4x8x - works in PCIEx16 - MB slot 1
@pawx - Sorry I missed your post and didn’t reply back in June!!
I sent you 12 or maybe 24 BIOS (not sure what all is in second set, didn’t look right now), but anyway, by now you should be abel to tell me which BIOS exactly affacted the slot you want to change now, do you not know?
If you do not know still, please use a graphics card and test all 12 initial BIOS with that card in the slot you want to change now, and see which BIOS cuts the PCIE Cards lanes down to x8 or x4 etc.
I can set any bifurcation allowed/possible on any given slot, but I don’t have this board so you have to tell me which BIOS setting (by way of which BIOS out of the 12) controls which slots setting.
From post #12-13 we know >> IOU1 = second PCIE slot - And this is all I can see clearly from your comments and results so far.
Post #14 does not help me any, I need full BIOS file names from what I sent you.
For post #15 results, what did you test in those slots? You said >> works in PCIEx8 - MB slot 2 << This not possible based on BIOS name, assume I set 4x4x bifurcation so x8 not possible, or the setting changed in that BIOS does not apply to this slot.
And saying “Works in slot” doesn’t tell me anything, what works there, and how is it working, being bifurcated, and if so to what etc?
For clarity here, from the get-go, you need to test all 12 BIOS I sent you with a single graphics card. Test each BIOS one by one, checking each slot one by one on each of the 12 BIOS.
To see which BIOS cuts it’s lane width down and in which slot, then give me results of all those tests so I can make an outline of what settings apply to which slots
Testing that way is easiest way to see the slot width being affected by BIOS in testing, or not.
Using Hyper for this is not best way, due to how it reacts with some bifurcation applied vs others, you could maybe see in HWINFO BUS area, but use only two cards and test all 12 BIOS w/ card in each slot one by one per each BIOS.
My notes on testing with Hyper II card, maybe help you with some oddities if you were not already aware
[REQUEST] Bifurcation Asus x99-a II - 5820k (2) (See post #16)
@Lost_N_BIOS
Thanks for the reply.
You have only sent me 5 different BIOS options, which were:
X79UD5NVMEIOU14x4x
X79UD5NVMEIOU24x4x8x
X79UD5NVMEIOU28x4x4x
X79UD5NVMEIOU34x4x8x
X79UD5NVMEIOU38x4x4x
And these were enough to figure out which IOU is which PCIE lane:
IOU1 = PCIE_2 (8x electrical)
IOU2 = PCIE_1 (full 16x)
IOU3 = PCIE_3 (full 16x)
I did further testing with a GPU. Here are the results:
IOU14x4x
PCIE_1 16X
PCIE_2 4X (both NVME SSD show up in windows - bifurcation works)
PCIE_3 16x
IOU24x4x8x
PCIE_1 8x (both NVME SSD show up in windows - bifurcation works)
PCIE_2 8x
PCIE_3 16x
IOU28x4x4x
PCIE_1 4x (NVME SSD will not boot)
PCIE_2 8x
PCIE_3 16x
IOU34x4x8x
PCIE_1 16x
PCIE_2 8x
PCIE_3 16x
IOU38x4x4x
PCIE_1 16x
PCIE_2 8x
PCIE_3 16x
It appears the IOU3 BIOS does nothing to the third slot. Do you have any idea why this might be so?
I did read that some motherboards might behave differently with the ASUS HYPER m.2 card - ex. only 1st and last slot on the card might work with bifurcation. But my m.2 carrier card only has 2 slots available so I cant test this.<br /><br />Any ideas for further changes to the BIOS? <br /><br />Thanks :)<br /><br />edit: As luck might have it, PCIE_3 slot is the one I need bifurcation to work on. Alternative solution might be to try and squeeze a flex ribbon PCIE riser under the fat GPU, but Im not sure it would fit.
@Lost_N_BIOS
Hey. I have another question.
I`ve downloaded AMIBCP 4.55 and opened the BIOS file. I see where the hidden menu is and where the PCIE lane "width" is assigned (16x, 8x8x, etc.) Is this the only change I need to make to have bifrucation or are there some other additional steps to perform?
Greetings and happy holidays.
Hello.
For anyone wondering.
After some testing and researching it appears that this motherboard "Gigabyte X79 UD5" only supports bifurcation on first two PCIE lanes.
I`ve solved my problem using a PCIE riser and by mounting the GPU vertically.
Greetings.
Has a final release been made for this Bios?