Yes, the SN2700 is loud — 1U, high-speed fans, no quiet mode. It also draws more than a lab switch. If it sits in a room you work in, this is the wrong switch. In a garage or basement, it is one of the cheapest routes to 32 × 100GbE ports.
How Loud Is an SN2700, Really?
The SN2700-CS2FC is a 1U chassis with 32 QSFP28 cages, a Spectrum ASIC and 6.4 Tb/s of switching capacity. It was designed for a data hall where nobody works within arm’s reach, and the cooling assumes it: small hot-swap fan trays spinning fast enough to move air through a 1U body.
Two things decide how loud yours will be. Inlet temperature is the big one — the fan curve follows the air going in, not the number of ports you have lit. A unit pulling 20 °C air in a cool basement settles into a steady low roar; the same unit in a 28 °C spare room runs noticeably harder all day. The second is boot: the fans go to full for a minute or two, then drop once the ASIC and supplies report temperature. Judge a desk test after five minutes, not thirty seconds.
There is no setting that pins the fans at a low fixed speed; Onyx manages airflow itself and will always choose cooling over quiet. A lightly loaded SN2700 in a 20–22 °C room is audible through a stud wall — a steady hum with a fan tone on top. Acceptable in a garage. Not acceptable in a room where you take calls.
What It Draws, and Where the Watts Go
Two hot-swap supplies, 100–240 V, standard C14 inlets, so the power side is easy. The variable is optics. A 100G QSFP28 module typically draws around 3–4 W; fill all 32 cages and you have added well over 100 W before the switch does any work. Add the ASIC, the fans and supply losses and a fully populated unit is a few hundred watts of continuous heat that has to leave the room.
Most home labs never get there. A handful of DACs and two uplinks leave the chassis idling at a fraction of its rating. The expensive mistake is buying the switch and then filling every cage because the ports are sitting there.
What Else You Need Before It Passes Traffic
Budget for the parts around the switch, not only the switch. A passive 100G copper cable is good to roughly 3 m; past that you need active copper or optics. If your servers are 25G, each 100G port can break out into four 25G links — the cabling and port settings for that are covered in Can You Run a 25GbE Card on a 100GbE Switch Port?.
Then there is what used units often arrive without: rails, and sometimes power cords. The SN2700 is a full-depth 1U chassis and a generic shelf in a deep rack is a poor substitute. Ask about the rail kit before you commit — it is the most commonly missing part on a used switch.
Which SN2700 Suffix Do You Need?
| Spec | SN2700 | What it means at home |
|---|---|---|
| Ports | 32 × QSFP28, 100GbE | More ports than most labs can fill |
| Breakout | 4 × 25G per port | Up to 128 × 25G, if the cables match |
| Switching capacity | 6.4 Tb/s | Not your limit; optics and power are |
| Latency | Under 3 µs port to port | Only matters if you run RDMA |
| Airflow | Front-to-back or back-to-front, per option code | Must match the direction your rack flows |
| Cooling | Hot-swap fan trays, automatic curve | Audible through a wall, no quiet mode |
| Power | Dual hot-swap supplies, 100–240 V | Optics are the real load, not the chassis |
| Software | Mellanox Onyx | Serial console needed before first configuration |
The family name does not tell you everything. Suffixes in the ordering code carry airflow direction, supply configuration and rail options, and airflow is the one detail that cannot be corrected later in software: a front-to-back unit in a back-to-front rack pushes hot exhaust into the cold aisle and runs hot for as long as it is powered. When you ask for a quote, send the full part number printed on the label, or tell us which way your rack flows and we will match the unit instead of guessing. The SN2700-CS2R and the CS2FC listing above are the same 32-port platform with different option codes.
On the server side, the natural pairing is an MCX516A-CCAT for 100G hosts, or an MCX4121A-ACAT if you are breaking out to 25G.
When the SN2700 Is the Wrong Switch
Be honest about three cases. First, if the rack is in the room where you work, no amount of tuning will make this pleasant — a low-speed or fanless 25G switch is the right answer. Second, if you need eight 25G ports and nothing else, a 32-port 100G chassis is a lot of heat and noise for the job. Third, if your roadmap is 200G or 400G per host, plan for that instead of buying twice; the SN3700-CS2FC is the next step in the same family and worth pricing before you commit to a fabric.
What the SN2700 is actually good at: a lab where you want a real leaf-spine fabric, where the servers carry 100G cards, and where the switch lives somewhere you do not. At that point the port count stops being overkill and becomes the reason you bought it. If you are still choosing between chassis, our NVIDIA Mellanox switch selection guide covers the port-count and role trade-offs, and 100GbE data center network design shows how leaves and spines are sized once you have more than one switch.
Frequently Asked Questions
Is the SN2700 too loud for a home lab?
It is a data center switch with a server-grade cooling path, so it runs a continuous low hum that is comparable to a small server rather than to a quiet desktop accessory. In a spare room or a cupboard it is usually fine. In a study or a living space it is a real consideration, and that is where a 25GbE alternative usually makes more sense.
What is the noise level of a Mellanox SN2700?
We do not publish a vendor noise figure for the unit, and we will not invent one. What we can say is that it is a 1U switch with server-grade fans and a cooling path designed for a data center, so the acoustic floor in a quiet room is clearly audible. If that matters for your space, tell us and we will talk through the quieter options.
Can I reduce the fan speed on an SN2700?
The fan curve can be adjusted through the network OS, and lowering it reduces noise, but it is a trade against thermals and can trigger an environmental alarm on the switch. In a domestic environment that alarm threshold may need adjusting too. It is workable, but the better question is whether you need a data center switch in that space at all.
What is the quieter alternative for a home lab?
A 10GbE or 25GbE switch is dramatically quieter and covers most home lab needs — NAS traffic, virtualisation host connectivity and management. 100GbE in a home lab is usually about learning the hardware rather than about throughput, so a quieter 25GbE path gets you the same education without the acoustic cost.
Will a used SN2700 be noisier than a new one?
Fan noise rises with bearing wear, so an older unit can be noisier. We test the chassis on our own line and report the fan condition and the observed noise behaviour per unit, so you are not discovering a worn fan at 2am. Ask for photos of the actual unit before you commit.
How do you verify a used SN2700 before shipping it?
We clean, re-flash and bench-test on our own test line, then confirm the port count, port speed, airflow direction, fan configuration and firmware level against the part number, and we test the fans under load. Ask for photos of the actual unit and the bench-test notes before you commit.
Can I keep an SN2700 in a home office?
Not comfortably. It is a data-center 1U switch with high-speed fans and no quiet mode, and it is audible through a wall. A garage, basement or utility closet is the realistic placement.
Does an SN2700 run 10GbE?
A 100G QSFP28 port can run 40GbE with a QSFP+ module or DAC, and can break out to 4 × 25G or 4 × 10G with the right cable and port setting. Set the speed explicitly rather than relying on autonegotiation.
Which operating system does it run?
Onyx is the native OS and what most units in the field were running. Some were deployed with Cumulus Linux, which carries a license of its own. Confirm what is loaded on the specific unit before you plan around it.
Do I have to use Mellanox optics?
No. Third-party coded QSFP28 modules usually work, and when a link refuses to come up the coding is the usual cause rather than the module itself. Send us the module part number and we will tell you what we have seen work.
How many 25G servers can one SN2700 feed?
Up to 128 × 25G if you break out every port, though most labs run fewer and keep some ports as 100G uplinks. Oversubscription is a design choice, not a limit of the switch.
The SN2700 variants listed on zhongxindata.hk are quoted per part number; other option codes we quote per part number. Send the part number and quantity and we will check availability. WhatsApp +86 13068616914 · zhongxindata.hk
What drives the noise on an SN2700
- The switch is a 1U data center part with a server-grade cooling path designed for a raised floor
- In a quiet room the fan curve has no reason to ramp down, and the acoustic floor is high
- The port speed and the transceiver power draw also contribute to the thermal load
Realistic expectations for a domestic space
- Expect a continuous low hum comparable to a small server, not a quiet desktop accessory
- In a rack in a spare room or a cupboard, this is usually tolerable and often unnoticed
- In a study or a living space it is a genuine quality-of-life issue worth planning around
Quieter alternatives and workarounds
- A 10GbE or 25GbE switch is dramatically quieter and enough for most home lab storage and virtualisation work
- Soundproofing the enclosure helps more than lowering the fan speed
- If you need 100GbE, the noise is a property of the platform — plan for a separate space
Related reading
- SN2700 100GbE switch — the switch this article is about
- This article — self reference
- 100GbE network design — the design context
- Network switches — category hub
Frequently Asked Questions
Is the SN2700 too loud for a home lab?
It is a data center switch with a server-grade cooling path, so it runs a continuous low hum that is comparable to a small server rather than to a quiet desktop accessory. In a spare room or a cupboard it is usually fine. In a study or a living space it is a real consideration, and that is where a 25GbE alternative usually makes more sense.
What is the noise level of a Mellanox SN2700?
We do not publish a vendor noise figure for the unit, and we will not invent one. What we can say is that it is a 1U switch with server-grade fans and a cooling path designed for a data center, so the acoustic floor in a quiet room is clearly audible. If that matters for your space, tell us and we will talk through the quieter options.
Can I reduce the fan speed on an SN2700?
The fan curve can be adjusted through the network OS, and lowering it reduces noise, but it is a trade against thermals and can trigger an environmental alarm on the switch. In a domestic environment that alarm threshold may need adjusting too. It is workable, but the better question is whether you need a data center switch in that space at all.
What is the quieter alternative for a home lab?
A 10GbE or 25GbE switch is dramatically quieter and covers most home lab needs — NAS traffic, virtualisation host connectivity and management. 100GbE in a home lab is usually about learning the hardware rather than about throughput, so a quieter 25GbE path gets you the same education without the acoustic cost.
Will a used SN2700 be noisier than a new one?
Fan noise rises with bearing wear, so an older unit can be noisier. We test the chassis on our own line and report the fan condition and the observed noise behaviour per unit, so you are not discovering a worn fan at 2am. Ask for photos of the actual unit before you commit.
How do you verify a used SN2700 before shipping it?
We clean, re-flash and bench-test on our own test line, then confirm the port count, port speed, airflow direction, fan configuration and firmware level against the part number, and we test the fans under load. Ask for photos of the actual unit and the bench-test notes before you commit.