I bought this board reading that bifurcation is possible, but turns out only x8x8 is available in the BIOS, whereas I need x8x4x4 for my riser.
Some boards have the PCI bifurcation setting in the PBS menu, but this one has very little there.
My understanding is this should be possible on this chipset/CPU - so hoping it can be unlocked in a modded BIOS.
Can anyone help with this please?
Support page: https://rog.asus.com/uk/motherboards/rog…l/helpdesk_bios
Latest BIOS: https://dlcdnets.asus.com/pub/ASUS/mb/So…G-ASUS-1803.ZIP
I see two results for the string "x8x4x4" in UEFI tool. Extracting the PE32 file and extracting IFR, I see the same in both:
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Form Sets
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Offset: Title:
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0x5FA8 AMD PBS (0x2 from string package 0x0)
Within there, the match for "x8x4" is:
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0x6124 Suppress If: {0A 82}
0x6126 Variable 0x2 equals value in list (0x1, 0x3, 0x4, 0x6) {14 8E 02 00 04 00 01 00 03 00 04 00 06 00}
0x6134 Not {17 02}
0x6136 End {29 02}
0x6138 Setting: PCIe/GFX Lanes Configuration, Variable: 0x11 {05 91 09 00 0A 00 08 00 01 00 11 00 10 10 00 03 00}
0x6149 Option: x16, Value: 0x0 (default) {09 07 0B 00 10 00 00}
0x6150 Option: x8x8, Value: 0x1 {09 07 0C 00 00 00 01}
0x6157 Option: x8x4x4, Value: 0x2 {09 07 0D 00 00 00 02}
0x615E Option: x4x4x4x4, Value: 0x3 {09 07 0E 00 00 00 03}
0x6165 End of Options {29 02}
0x6167 End If {29 02}
0x6169 Suppress If: {0A 82}
0x616B Variable 0x2 equals value in list (0x5) {14 88 02 00 01 00 05 00}
0x6173 Not {17 02}
0x6175 End {29 02}
0x6177 Setting: PCIe/GFX Lanes Configuration, Variable: 0x11 {05 91 09 00 0A 00 09 00 01 00 11 00 10 10 00 02 00}
0x6188 Option: x16, Value: 0x0 (default) {09 07 0B 00 10 00 00}
0x618F Option: x8x8, Value: 0x1 {09 07 0C 00 00 00 01}
0x6196 Option: x8x4x4, Value: 0x2 {09 07 0D 00 00 00 02}
0x619D End of Options {29 02}
0x619F End If {29 02}
I've seen guides on enabling the PBS menu itself ([OFFER] Gigabyte GA-AX370-Aorus Gaming 5 BIOS mod (12)), but not individual items within the menu.
In my case the BIOS already shows the PBS menu, but not these bifurcation options.