NVLink - Revision history

ImportBot: NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @onemillionkates, @_arcanum_, @ghostinthedatacenter_87281, @bigptoughneigh, @ob88594, @djpandaman, @wakeupmbrc1

2026-10-30T10:02:18Z

NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @onemillionkates, @_arcanum_, @ghostinthedatacenter_87281, @bigptoughneigh, @ob88594, @djpandaman, @wakeupmbrc1

ImportBot: NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @ghostinthedatacenter_87281, @bigptoughneigh, @djpandaman, @wakeupmbrc1

2026-10-30T08:49:22Z

NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @ghostinthedatacenter_87281, @bigptoughneigh, @djpandaman, @wakeupmbrc1

← Older revision		Revision as of 08:49, 30 October 2026
Line 42:		Line 42:
	NVIDIA 900-53651-0000-000. {{Source\|djpandaman\|2026-10-06\|https://discord.com/channels/1518634379604136178/1518692084729511967/1557060154409881651}}		NVIDIA 900-53651-0000-000. {{Source\|djpandaman\|2026-10-06\|https://discord.com/channels/1518634379604136178/1518692084729511967/1557060154409881651}}
	Chinese clone bridges are on Alibaba for about $200; a Taobao supplier quoted RMB780 unbranded / RMB900 NVIDIA for the		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. {{Source\|djpandaman\|2026-10-07\|https://discord.com/channels/1518634379604136178/1534370835220004885/1557418364190593166}}		dual-slot 900-53651-0000-000, bought via Superbuy; on xianyu about $120 each. US retail is 150+ USD plus tax.
	~~Supplier names are in the buying lane's notes; this page sticks to part numbers.~~		{{Source\|djpandaman\|2026-10-07\|https://discord.com/channels/1518634379604136178/1534370835220004885/1557418364190593166}}

	== Is it worth it? ==		== Is it worth it? ==

ImportBot: NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @ghostinthedatacenter_87281, @bigptoughneigh, @djpandaman, @wakeupmbrc1

2026-10-30T08:04:50Z

NVLink on the CMP 170HX: fused off, not publicly unlocked, the missing board components, bridge part numbers and why it would only help diffusion. Discord Oct 2026.; sources: @lia_oc, @cute_sc2, @_orrorin, @ghostinthedatacenter_87281, @bigptoughneigh, @djpandaman, @wakeupmbrc1

New page

{{Unlock
|unlocks=NVLink
|variant=both
|driver_version=n/a
|unlock_build=none public
|steps_page=NVLink
|status=Theory
|source=https://discord.com/channels/1518634379604136178/1534501623471145011/1556555596088746037
}}

'''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|https://discord.com/channels/1518634379604136178/1518695328008638516/1562930961207922811}}

== What blocks it ==

* '''Fuse:''' <code>OPT_NVLINK_DISABLE</code> reads <code>0x2</code> 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|https://discord.com/channels/1518634379604136178/1534501623471145011/1556555596088746037}}
* '''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|https://discord.com/channels/1518634379604136178/1518695328008638516/1559037159841988619}}
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|https://discord.com/channels/1518634379604136178/1518692084729511967/1562898774769274960}}

== 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|https://discord.com/channels/1518634379604136178/1518695328008638516/1563312993414946827}}
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|https://discord.com/channels/1518634379604136178/1518692084729511967/1557060154409881651}}
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. {{Source|djpandaman|2026-10-07|https://discord.com/channels/1518634379604136178/1534370835220004885/1557418364190593166}}
Supplier names are in the buying lane's notes; this page sticks to part numbers.

== 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|https://discord.com/channels/1518634379604136178/1518692084729511967/1564684364896276554}}
Pairs only (TP2) on A100-class PCIe; combining more than two cards over bridges is unresolved.

== Status ==

{{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]].

{{ImportFooter}}
[[Category:Unlocks]]
[[Category:8 GB]]
[[Category:10 GB]]

← Older revision		Revision as of 10:02, 30 October 2026
Line 17:		Line 17:
	* '''Fuse:''' <code>OPT_NVLINK_DISABLE</code> reads <code>0x2</code> on the 10 GB probe; CUTE measured the connector		* '''Fuse:''' <code>OPT_NVLINK_DISABLE</code> reads <code>0x2</code> 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.		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\|https://discord.com/channels/1518634379604136178/1534501623471145011/~~1556555596088746037~~}}		{{Source\|handle=cute_sc2\|date=2026-10-05\|link=https://discord.com/channels/1518634379604136178/1534501623471145011/1556562554719965275}}<br />
			{{Source\|handle=cute_sc2\|date=2026-10-05\|link=https://discord.com/channels/1518634379604136178/1534501623471145011/1556562874342572094}}
	* '''Missing microcode:''' GA100 has three on-die MINION microcontrollers for link training; the 170HX VBIOS lacks the		* '''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.		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		* '''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.		terminations; the expected failure mode of unterminated NVLink is inability to train.
	{{Source\|_orrorin\|2026-10-12\|https://discord.com/channels/1518634379604136178/1518695328008638516/~~1559037159841988619~~}}		{{Source\|handle=_orrorin\|date=2026-10-12\|link=https://discord.com/channels/1518634379604136178/1518695328008638516/1559264615911923833}}
	The 3.3 V NVLink clock generator parts are also missing; kater found U11 (the bridge clock generator,		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.		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\|https://discord.com/channels/1518634379604136178/1518692084729511967/~~1562898774769274960~~}}		{{Source\|handle=onemillionkates\|date=2026-10-05\|link=https://discord.com/channels/1518634379604136178/1534501623471145011/1556788730717675702}}<br />
			{{Source\|handle=_arcanum_\|date=2026-10-07\|link=https://discord.com/channels/1518634379604136178/1534501623471145011/1557248811351539713}}<br />
			{{Source\|handle=ghostinthedatacenter_87281\|date=2026-10-22\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1562905010692558939}}

	== Status of the hardware mod ==		== Status of the hardware mod ==
Line 32:		Line 35:
	to share though." GhostInTheDatacenter has about 75% of the NVLink circuit components and is waiting on 50 milliohm		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.		resistors plus parts to re-enable the power stages; if it works he will document a BOM.
	{{Source\|bigptoughneigh\|2026-10-23\|https://discord.com/channels/1518634379604136178/1518695328008638516/1563312993414946827}}		{{Source\|bigptoughneigh\|2026-10-23\|https://discord.com/channels/1518634379604136178/1518695328008638516/1563312993414946827}}<br />
			{{Source\|handle=ghostinthedatacenter_87281\|date=2026-10-24\|link=https://discord.com/channels/1518634379604136178/1518695328008638516/1563603290145423391}}<br />
			{{Source\|handle=ghostinthedatacenter_87281\|date=2026-10-25\|link=https://discord.com/channels/1518634379604136178/1518695328008638516/1563706962703683687}}
			OB88594's advice for the missing parts: add the components that are missing and follow the A100 layout.
			{{Source\|handle=ob88594\|date=2026-10-24\|link=https://discord.com/channels/1518634379604136178/1518695328008638516/1563420061710950601}}
	mrpandagod is working on the software side after the RIR unlock and says it looks like it will work; he rewrote the SEC2		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.		payload for NVLink during experiments. Nothing public as of 2026-10-28.
Line 40:		Line 47:
	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		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),		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\|https://discord.com/channels/1518634379604136178/1518692084729511967/~~1557060154409881651~~}}		NVIDIA 900-53651-0000-000. {{Source\|handle=djpandaman\|date=2026-10-06\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1557070037209317407}}<br />
			{{Source\|handle=djpandaman\|date=2026-10-06\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1557074851594899527}}
	Chinese clone bridges are on Alibaba for about $200; a Taobao supplier quoted RMB780 unbranded / RMB900 NVIDIA for the		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.		dual-slot 900-53651-0000-000, bought via Superbuy; on xianyu about $120 each. US retail is 150+ USD plus tax.
Line 49:		Line 57:
	Miséricorde: NVLink would help only diffusion workloads and would need higher power limits, so it would not change much		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%.		for LLM inference; for GLM 5.3 Flash in TP4 it might add roughly 20-25%.
	{{Source\|wakeupmbrc1\|2026-10-27\|https://discord.com/channels/1518634379604136178/1518692084729511967/~~1564684364896276554~~}}		{{Source\|handle=wakeupmbrc1\|date=2026-10-18\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1561400562036248677}}<br />
			{{Source\|handle=wakeupmbrc1\|date=2026-10-27\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1564684409029005334}}<br />
			{{Source\|handle=wakeupmbrc1\|date=2026-10-27\|link=https://discord.com/channels/1518634379604136178/1518692084729511967/1564684449642193021}}
	Pairs only (TP2) on A100-class PCIe; combining more than two cards over bridges is unresolved.		Pairs only (TP2) on A100-class PCIe; combining more than two cards over bridges is unresolved.