Yes it is possible, you could try to use this bios (DWYOR): X99-AUSB3.1 MOD.rar (7.5 MB)
Bios 4101: Stock with rebar support
Bios 4102: Same but with ME 9.1.40 (stock was 9.1.37)
To Activate it, disable CSM (is a must), enable Above 4G Decoding in bios (if there is none, follow this guide), and use ReBarState.EXE app and set it to 32, enter, and reboot.
What is your motherboard ? Only the listed models need DSDT patching
MSI B450 Tomahawk.
What I was trying to do, now MSI B450 Tomahawk motherboards have ReBar option in recent BIOSes however I was on an old BIOS which did not because that BIOS version allows me to use PCIe 4.0, they took that away in later BIOS versions so I thought if I used this patch it would work afterwards.
I have option to enable 4G encoding in that old BIOS but when I turn it on, Windows gets stuck in infinite boot. UEFI mode on, Windows is on GPT.
Just insert the rebardxe using latest mmtool v5 (in this case i did use MMTool 5.2.0.25) on GUID A0327FE0-1FDA-4E5B-905D-B510C45A61D0 (insert using Insert As Is option) is enough.
Did this to B450M Gaming (gigabyte) and it’s safe to do so.
@hyt54 you might be able to fix boot logo stuck by DSDT patch but FYI no one has patched AM4 DSDT before. Maybe you could post it here ?
Hello. Someone help me with above 4g with asrock z87 extreme 4, thats not in hidden options, even as in extracted file from body section of dxe driver from bios? I try modiffy bios, but Im stuck at compliing dsdt with iasl - shows 3 errors and aml file wasn’t created.
Strange is that in z87 extreme 4 from bios 2.9 4g decode is in bios options (hidden but it is there), and even in later z97 motherboards in all bios versions 4g decocing is there, but in z87 in all bios versions, 4g decode option is gone - only amibcp455 shows 4g decode in “bios strings” with “token” thats absent in setup configuration.
Someone helps:
Hello @Dider,
Is this mod required for your GPU?
If so, you might try setting ReBAR to 256MB, 512MB, 1GB and 2GB and testing it for performance improvements. You might find that the improvements drop off as you get to 2GB. In which case, you can save yourself the effort of trying to get the full BAR size working.
I have inthe ARC A770 and the intel driver stopped complaining about ReBAR not being activated when I got to 2GB.
Best regards,
-68k
@Dider hi
no one has figured out how to add 4G decoding if the option is missing (even in hidden) so far, the only way you can make it work is through using Linux and DSDT modification. The DSDT modification page says how to fix the errors if they aren’t there then mention what they are
I Just ask, wona try - i don’t now it is required. Only adding rebar.dxe to bios i can set re bar to 1GB max -when try 2GB bios no start. But I haven’t 4g decode enabled (and large memory too).
I write to asrock, about 1 year ago, and they writeback, that they start support for rebar with intel z390, and now I found winraid forum, and z170, z97 and even z77 worked 4g decode, so i try that on my z87, but as you see on my topic - my bios don’t has this varstore options.
Now I "play " with HeX editing som writes, but copy/paste from z77 or z97 is way too far for my knowledge abuot it.
THX for replay68k-dude
I try dsdt modification, but I can’t compile to asl file - iasl shows 3 errors and dont create aml file. Oh, and I dont have/use linux.
Hello, i have AsRock IMB-180 motherboard with Haswell i7-4900MQ cpu and RX 590. Before trying to inject the dxe driver into my bios i would like to figure out if its possible to make the ReBar to function properly on my system since i have some doubts. First of all, GPU-Z shows no for GPU hardware support, Above 4G decode and Resizable BAR enabled in bios. When i check my bios image with AMIBCP there is no Resizable BAR enable option at all and i can find above 4G decoding only in the bios strings but there is nothing in setup configurator. Is it possible to somehow enable above 4g decoding and ReBAR on my system? PS when i try enabling hidden 4G decoding setting in bios, there is nothing about 4G decoding in my bios IRF extracted file which is weird
Hello @karalux,
It may not be possible to enable above 4g decoding.
I have seen posts from people who have ReBAR working on these cards.
I would add the ReBarDxe.ffs to the latest bios file. Then set ReBAR to 256MB, 512MB, 1GB and 2GB and testing it for performance improvements. You might find that the improvements drop off as you get to 2GB. In which case, you can save yourself the effort of trying to get the full BAR size working.
If at any point it fails to boot, clear the CMOS and set the last value that worked.
Best regards,
-68k
Edit: See here for a list of working boards and cards. List of working motherboards · Issue #11 · xCuri0/ReBarUEFI · GitHub
Ive done the mod with 1024MB and i am not 100% sure if its working or not since im not getting the Large Memory in device manager. Tried a couple of games and in UE4 performance seems to be more or less the same but in Amnesia The Bunker i get a really bad stuttering and it looks like gpu is not utilising more than around 1.5G of VRAM. Should i try DSDT patching since i have a Haswell system?
EDIT: Anything more than 1024G is preventing pc to post, it goes to black screen when turned on. Oh, and im not getting the Large Memory because Above 4G Decoding is not enabled, right?
@karalux Unless you have full BAR size (8GB in this case) you will get issues like that. You need 4G decoding to use more than 1GB
I’m running 8GB BAR on my RX 580 8GB and every game works fine.
Any ideas how to enable above 4g decoding manually when AsRock didnt put a setting for it in my MB bios?
@karalux No unless you use Linux along with modified DSDT. Maybe someone else here can figure out module swapping or something
I don’t really know what I’m doing. Bios modding is never something i got into and i don’t wanna risk breaking something. Could someone who knows what they are doing apply the Resizeable Bar patch to Bios verison f41 ?
Hi to all
i have a Asus P8Z68-V-LX , i try to ability a Resizable Bar.
I search to apply the DSDT patch, when compile i have this compli i have this error:
DSDTMod.dsl 11512: Name (_HID, “ABCDEFGH”) // _HID: Hardware ID
Error 6035 - ^ _HID suffix must be all hex digits (GH)
Can i help me.
Very Very Thank a lot.
just insert the rebardxe.ffs to guid A03 (usually most bottom before PEI part) and you’re good to go.
