If you’re buying an NVIDIA GB10 / ConnectX-7 class “desktop supercomputer” (like ASUS Ascent GX10) or building a compact 400G lab interconnect, the cable matters more than people expect. The ASUS QSFP QUAD 400G GX10 Pluggable Cable sold on NationalPC is a short 0.4m direct-attach copper (DAC) designed for high-bandwidth, low-latency device-to-device or device-to-switch links, with a strong emphasis on stacking / interconnect use in dense setups.

What this cable is (and why it exists)

From ASUS’ own GX10 documentation, the accessory is explicitly listed as a “QSFP112 400G 0.4M DAC cable”, using PAM-4 modulation and 112G per lane to reach 400G total bandwidth—in other words, it’s meant for modern 400G-class ports rather than older QSFP28-era 100G links.

Short DAC cables like this are commonly used:

  • inside a rack / between adjacent devices (low clutter, low power, simple install),

  • where latency and signal stability matter, and

  • where you want reliable, repeatable bring-up without dealing with separate optics + fiber. (This is the same “DAC vs AOC/optics” decision enterprise switch vendors document for 400G ecosystems.)

Key specs (pulled from ASUS datasheet)

These are the most important “hard facts” buyers should match with their hardware ports:

  • Model: QSFP112 400G 0.4m DAC cable

  • Cable type/medium: Copper

  • Data rate: 112G per lane (enabling 400G total)

  • Application: Ethernet PAM-4 applications

  • Connector type: QSFP112

  • Length: 0.4m (400mm)

Practical meaning: this cable is designed for very short, very fast links—perfect for stacked/adjacent devices and tidy lab benches.

Where it fits best: ASUS GX10 stacking and ConnectX-7 networking

ASUS positions the Ascent GX10 as a compact system with NVIDIA ConnectX-7, and the same datasheet calls out dual GX10 system stacking enabled by ConnectX-7 networking for greater scalability.

So the “ideal” use case is straightforward:

  • You have two compatible 400G-capable ports (QSFP112-class),

  • You want a direct, short interconnect,

  • You want a cable that’s known-good for that platform, minimizing negotiation and compatibility surprises.

That “known-good” part is why OEM-branded cables still sell even when generic 400G DACs exist: at 400G, signal integrity and firmware/EEPROM compatibility can be the difference between “link up instantly” and “mysterious flaps.”

Hot-plugging, downtime, and what “pluggable” really implies

Vendors often describe these as “pluggable / hot-pluggable,” but here’s the expert nuance:

  • Physically hot-plugging a DAC is normal for QSFP ecosystems.

  • Whether you can do it without downtime depends on your topology:

    • If it’s a redundant fabric or bonded link, you can swap without user-visible impact.

    • If it’s a single point-to-point stack link, you’ll still interrupt that interconnect when you pull it.

So yes—installation is easy, but “no downtime” is environment-dependent, not magical.

Compatibility reality check: QSFP112 vs QSFP-DD / QSFP56 confusion

A lot of 400G discussions mix QSFP112, QSFP-DD, and breakouts (400G → 2×200G, etc.). Even NVIDIA community threads for GB10/DGX Spark show confusion around what exact QSFP type is supported and which cable SKUs are “approved.”

What you should do before buying (critical):

  1. Confirm the port type on BOTH ends (QSFP112 vs QSFP-DD vs QSFP56).

  2. Confirm whether you need straight 400G-to-400G, or a breakout cable.

  3. If it’s for a specific platform (GX10 / Spark / EdgeXpert class systems), prefer approved/validated cables when possible, because 400G links can be picky.

The ASUS datasheet explicitly calls this accessory QSFP112. That’s your anchor.

Performance expectations (what this cable helps you achieve)

A DAC cable itself doesn’t “increase” bandwidth—it enables your hardware to run at its rated link speed reliably.

In practical terms, a solid 0.4m 400G DAC helps with:

  • Stable training / distributed workloads where the interconnect is constantly active,

  • Fast data movement between stacked systems (dataset shards, checkpoints),

  • Low-latency paths for communication-heavy workloads.

Also, because it’s short copper, it’s typically:

  • easier to cable-manage,

  • less airflow-blocking than thick long copper runs,

  • and avoids the complexity of optics for very short distances. (Optics/AOCs become more attractive as distance increases.)

Build quality and “signal integrity” — why OEM parts still matter

At 400G, signal margins tighten. Switch and networking ecosystems talk a lot about 400G connectivity options (DAC/AOC/optics) and the importance of using supported parts.

Why the ASUS cable can be worth it:

  • It’s documented as part of the GX10 ecosystem (and even included in-the-box in the datasheet content).

  • For platform stacking, you generally want the simplest, validated path.

If you’re building a mixed-vendor setup, you can often use compatible 400G cables—just be ready to validate:

  • link comes up cleanly,

  • no CRC storms / retransmits,

  • stable under sustained load.

Who should buy this cable

Buy it if:

  • You have ASUS Ascent GX10 and want the correct short 400G interconnect for stacking / high-speed linking.

  • Your devices are adjacent/stacked and a 0.4m run is perfect.

  • You want the safer “OEM accessory” option for fewer compatibility surprises.

Skip it (or double-check) if:

  • Your hardware ports are QSFP-DD or QSFP56 and not QSFP112 (don’t assume “400G = same connector”).

  • You need longer distance than 0.4m (consider AOC/optics for longer runs).

  • You actually need a breakout (e.g., 400G → 2×200G), which is a different cable type.

Buying note (nationalPC)

NationalPC lists this cable as https://nationalpc.in/cables-and-adapters/asus-qsfp-quad-400g-gx10-pluggable-cable

FAQ

Is this the same as “ConnectX-7 stacking cable”?
It’s an ASUS accessory documented for the GX10 ecosystem and aligns with the ConnectX-7, 400G-class stacking story in the ASUS datasheet.

Can I stack ASUS GX10 with another GB10 system from a different brand using this?
Only if the port type and supported cable/EEPROM expectations match on both devices. NVIDIA community discussions around GB10/DGX Spark show that approved cable SKUs matter and that QSFP type confusion is common—so validate carefully.

DAC vs AOC vs optics—what should I pick?
For very short links, DAC is usually the simplest. As distance grows, AOC/optics become more attractive for manageability and reach—this is consistent with how major networking ecosystems describe 400G cabling options.

Verdict

As a purpose-built 0.4m QSFP112 400G DAC, this ASUS cable is exactly what you want for clean, stable, short-range 400G interconnects—especially for the ASUS Ascent GX10 stacking use case that ASUS itself documents. If your setup is mixed-vendor, treat this as a “best when matching ASUS/GX10” option and verify port type (QSFP112) before you buy.