NVLink

NVLink

Theory 8 GB and 10 GB
Driver	n/a
Unlock build	none public
Steps	NVLink
Source	Discord message
Confirmations	None yet. Confirm on your own card

NVLink is not publicly unlocked on the CMP 170HX, on either card. It is fused off and also missing board components. The 8 GB card has no NVLink path at all; the 10 GB card may be reachable with a hardware mod that is not public. Source: @lia_oc, 2026-10-22

What blocks it

• Fuse: OPT_NVLINK_DISABLE reads 0x2 on the 10 GB probe; CUTE measured the connector

 pins on 8 cards (all populated, pins connected to the core) and believes NVLink is blocked by GPU fuses.
 Source: @cute_sc2, 2026-10-05

• Missing microcode: GA100 has three on-die MINION microcontrollers for link training; the 170HX VBIOS lacks the

 bootstrap image. The VBIOS is not cryptographically signed, so injecting the image is the plan, but it is not done.

• Missing board parts: someone counted 5 resistors present on the A100 PCB that are absent on the 170HX, plus 3

 terminations; the expected failure mode of unterminated NVLink is inability to train.
 Source: @_orrorin, 2026-10-12
 The 3.3 V NVLink clock generator parts are also missing; kater found U11 (the bridge clock generator,
 GS7612S5MA-R, on the back of the PCB near the IO shield) is unpopulated, so the bridge clock never comes up.
 Source: @ghostinthedatacenter_87281, 2026-10-22

Status of the hardware mod

Big Ptoughneigh: "it works fine, but requires a very simple hardware mod (easier than the x16 mod). It's not my finding to share though." GhostInTheDatacenter has about 75% of the NVLink circuit components and is waiting on 50 milliohm resistors plus parts to re-enable the power stages; if it works he will document a BOM. Source: @bigptoughneigh, 2026-10-23 mrpandagod is working on the software side after the RIR unlock and says it looks like it will work; he rewrote the SEC2 payload for NVLink during experiments. Nothing public as of 2026-10-28.

Bridges (for when it works)

A100-class PCIe cards use 3 bridge slots; each bridge carries 4 NVLinks (200 GB/s per bridge, 600 GB/s per pair), so an 8-card rig would need 12 bridges. Compatible parts: PNY RTXA6000NVLINK-KIT (2-slot), PNY RTXA6000NVLINK3S-KIT (3-slot), NVIDIA 900-53651-0000-000. Source: @djpandaman, 2026-10-06 Chinese clone bridges are on Alibaba for about $200; a Taobao supplier quoted RMB780 unbranded / RMB900 NVIDIA for the dual-slot 900-53651-0000-000, bought via Superbuy; on xianyu about $120 each. US retail is 150+ USD plus tax. Source: @djpandaman, 2026-10-07

Is it worth it?

Miséricorde: NVLink would help only diffusion workloads and would need higher power limits, so it would not change much for LLM inference; for GLM 5.3 Flash in TP4 it might add roughly 20-25%. Source: @wakeupmbrc1, 2026-10-27 Pairs only (TP2) on A100-class PCIe; combining more than two cards over bridges is unresolved.

Status

Theory: no public software or hardware unlock, only in-progress hardware experiments. The 8 GB card has no path.

Related

VBIOS and firmware, Full SM unlock, Platforms, Cooling and power, 10 GB card.

Imported from the cmpunlocker Discord with credit; see Credits.