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PCIe Gen3 on the 10 GB card

From CMP Wiki
Revision as of 08:04, 30 October 2026 by ImportBot (talk | contribs) (Gen3 (and reported Gen4) link training on the 10 GB card after the RIR burn; commands from lixiangwuxian/170hx_tips and evanrodgers; Discord Oct 2026. 8 GB card cannot do this.; sources: @lxtend, @djpandaman, @wakeupmbrc1, @darkshad03, @dany0_; GitHub evanrodgers/cmp-170hx-rir-burn-util, lixiangwuxian/170hx_tips)
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PCIe Gen3 link (10 GB card)
Proven 10 GB
Drivernvidia-open 615.71.09 (reference) / 610.43.03
Unlock buildlixiangwuxian/170hx_tips + 170hx-rir-tool
StepsPCIe Gen3 on the 10 GB card
Sourcelink
Confirmations
Reproduced by @djpandaman (10 GB), 2026-10-11 · details

Warning 10 GB card only. It needs the permanent RIR fuse burn first. The 8 GB card cannot reach Gen3: its Gen3-disable fuse register is locked and there is no free RIR to clear it (see below).

Why the 8 GB card is stuck at Gen2

Gen3 and Gen4 are real fuses (OPT_DISABLE_GEN3_SPEED, OPT_PCIE_BOOT_GEN3_DISABLE), unlike the Gen2 bootstrap bypass. You cannot retrain at 8 GT/s with the disable fuse set. Source: @djpandaman, 2026-10-08 On the 8 GB card that fuse register is locked and there is no spare RIR to clear it, so Gen3 "retrain" is blocked. Source: @wakeupmbrc1, 2026-10-18 A probe on a 10 GB card confirms all three Gen3 fuses read 1 at stock (OPT_DISABLE_GEN3_SPEED=1, OPT_PCIE_BOOT_GEN23_DISABLE=1, OPT_PCIE_BOOT_GEN3_DISABLE=1), which is why the gate must be opened first. Source: @darkshad03, 2026-10-04

Prerequisites

  • 10 GB card (10de:2082), RIR fuse burn done (disable_sw_override cleared).
  • A working cmpunlocker-style driver already initialising the card (this does not do the memory
 unlock).
  • Reference driver nvidia-open 615.71.09 (the guide's), or 610.43.03 (the evanrodgers wrapper's).

Steps (lixiangwuxian/170hx_tips)

The process lives in Gen3_unlock_en.md (@lxtend). It has three parts: a probe-time fuse software override, a post-GSP Gen3 register sequence inside the driver, and RM link training. Only LnkSta: Speed 8GT/s counts as success, not LnkCap or LnkCtl2.

Module parameters (merge into your existing config, keep one value per key):

options nvidia NVreg_RegistryDwords="RmForceEnableGen2=1;RMPcieLinkSpeed=0x5;CmpGen3=1" cmp_fuse_gen3=0

RMPcieLinkSpeed=0x5 is a bitfield that allows Gen3; it does not mean "generation five". CmpGen3 is a custom registry key read by the patch. cmp_fuse_gen3 is not a stock NVIDIA parameter, so you must build the patched module that defines it; adding it to a stock driver does nothing. For Gen3, set only cmp_fuse_gen3=0; do not also set cmp_fuse_gpc=0, cmp_fuse_tpc*=0 or cmp_fuse_flr=1.

Key registers the patch touches (BAR0): EN_SW_OVERRIDE 0x00820040, DISABLE_SW_OVERRIDE 0x00820084, OPT_DISABLE_GEN3_SPEED 0x00820250 bit 0, OPT_PCIE_BOOT_GEN3_DIS 0x00820580 bit 0. The post-GSP Gen3 block sits in kgspBootstrap_TU102, gated on device id 0x2082 and CmpGen3=1, and finishes with a Gen1 to Gen2 to Gen3 retrain via the RM control NV2080_CTRL_CMD_BUS_SET_PCIE_SPEED (0x20801805, a 4-byte generation value, not MB/s).

Rollback: cmp-pcie-speed 2 returns to Gen2 at runtime; setting CmpGen3=0 is not a runtime undo. Full write-up and the ready-made wrapper: [https://github.com/evanrodgers/cmp-170hx-rir-burn-util evanrodgers/cmp-170hx-rir-gen3], which validated Gen3 x4 at boot on two cards with a 30-minute clean stress run.

Numbers / state

  • lxwx got Gen3 working on a 10 GB card on 2026-10-12 (his slot is x4, so Gen3 x4 equals Gen1 x16 bandwidth; his board
 is PCIe 3.0, so Gen4 was untested). Source: @lxtend, 2026-10-12
  • mrpandagod has done Gen3 and Gen4 on 10 GB cards via the RIR route.
 Source: @djpandaman, 2026-10-11
  • Gen4 behind a PLX switch was validated by mrpandagod (his motherboard is only Gen3).
 Source: @djpandaman, 2026-10-09
  • x16 width needs the capacitor mod. Without the caps, Gen4 falls back to 8.0 GT/s (Gen3).
 Source: @djpandaman, 2026-10-08

Known issues

  • Warning A Gen3 transition lost a card on one machine (RM 0x0f, fell off the bus); recover with a reboot or
 power cycle. That card's PCIe controller was later judged physically damaged. (170hx_tips Validation record.)
  • The guide was validated only on the 10 GB card (10de:2082); 10de:20c2 is untested and
 blocked anyway.
  • On 170hx-rir-tool the volatile --sw-write gen3 0 opens the fuse bits but the link can stay
 at Gen2; most overrides must happen at init/boot, which is why the driver-side patch is needed.
 Source: @lxtend, 2026-10-11
  • Contested whether Gen3 is consistent enough across cards to call "unlocked"; some think it needs a soldering iron or
 will not generalise. Source: @dany0_, 2026-10-07
  • A longer Gen3 write-up by @lxtend (the 170hx_tips repo) and an earlier XCE/CYA patch analysis by @replacedriver47
 exist; see Discord.

Status

Reproduced on more than one 10 GB card (lxwx, then mrpandagod and evanrodgers independently), so Proven on the 10 GB card. See the confirmation below.

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