MikroTik CRS504-4XQ-IN Cloud Router Switch 650MHz 4xQSFP28 C

The Verdict

Let me be blunt about the MikroTik CRS504-4XQ-IN: this is not a switch for everyone. It’s a niche product aimed at homelab enthusiasts, small ISPs, and media professionals who need 100G connectivity without selling a kidney. At roughly $1,000 (check current pricing — it fluctuates), you’re getting four QSFP28 ports that can run at 100G, 40G, or break out to 4x25G/4x10G. That’s absurd value on paper. The real question is whether the compromises are worth it. I’ve dug through 175 Amazon ratings (3.5 stars average) and the user forums to give you the unvarnished picture.

What’s actually in the box

The CRS504-4XQ-IN ships with the switch itself, a standard IEC power cable, a rackmount kit, and a printed quick-start guide. No DAC cables, no transceivers, no console cable. You’ll need to source QSFP28 modules or breakout cables separately — budget an extra $50-$150 per port depending on whether you go MikroTik-branded or third-party. The unit itself is compact: 1U rack-mount form factor, roughly 17.5 x 8.7 x 1.7 inches, and notably light at around 4.4 pounds. The aluminum chassis doubles as the heatsink — that’s the entire cooling solution, and it shows.

Performance and real-world use

Here’s where the CRS504 gets interesting and frustrating simultaneously. As a pure L2 switch, it handles wire-speed 100G forwarding without breaking a sweat. The Marvell Prestera switch chip is genuinely capable, and for storage workloads — think NVMe-oF, iSCSI, or NAS aggregation — it’s a monster. I’ve seen forum reports of sustained 90+ Gbps throughput on L2 with zero dropped packets.

The problem starts when you need L3 routing. The 650MHz CPU is a dinosaur, and RouterOS’s software routing caps out around 2.5 Gbps total. That’s not a typo. If you need inter-VLAN routing at 100G, this switch will choke. One Amazon reviewer put it plainly: “Great for switching, but don’t expect to route anything faster than gigabit without hardware offload.” You can enable hardware offload for specific simple static routes, but anything dynamic (OSPF, BGP) forces the CPU path. That’s a hard limitation, not a configuration issue.

What buyers consistently praise

The silence is the headline feature. Multiple reviewers highlight the fanless design as a game-changer. One wrote: “My previous 40G switch sounded like a jet engine. This thing is completely silent in my office closet.” For anyone running gear in a living space, that’s genuinely valuable. The build quality also gets consistent props — the aluminum chassis feels premium, and the port layout is logical with status LEDs that are actually readable.

The price-to-performance ratio for L2 workloads is another consistent theme. Another reviewer noted: “For 100G storage networking, nothing else comes close at this price. We run two of these for our render farm and they’ve been rock solid for six months.”

Where it falls short

Heat is the elephant in the room. The passive cooling works, but it works by radiating heat into whatever room the switch lives in. Chassis temps of 65-75°C are normal — I’ve seen reports of 80°C+ in warmer environments. You cannot rack this in an enclosed cabinet without active airflow or it will thermal-throttle. Several one-star reviews are people who cooked their units in unventilated racks. This is not a set-and-forget device.

Cable compatibility is the second pain point. QSFP28 DAC cables from generic vendors frequently fail to link. MikroTik’s own cables work fine, but they’re pricier. One reviewer summed up the frustration: “Spent two days troubleshooting a link that wouldn’t come up. Swapped to a MikroTik-branded DAC and it worked instantly.” Check your cable vendor’s compatibility list before buying.

Who should buy this

This is for you if: you’re building a 100G storage backbone and need silent operation; you’re a small ISP doing L2 aggregation; or you’re a homelab enthusiast with deep pockets who wants to learn 100G networking. Skip it if you need serious L3 routing, if your rack is poorly ventilated, or if you want plug-and-play compatibility with random third-party optics.

FAQ

Q: Can I use 40G QSFP+ modules in the QSFP28 ports? A: Yes, backward compatible. The ports negotiate down to 40G automatically. Many users run 40G for the lower cable cost and power draw.

Q: Does it support breakout cables (1x100G to 4x25G)? A: Yes, both RouterOS and SwOS support breakout. But test your breakout cables before deploying — compatibility is hit-or-miss with non-MikroTik cables.

Q: Is SwOS or RouterOS better for this switch? A: SwOS is simpler and faster for pure L2 switching. RouterOS adds routing features but at the CPU bottleneck mentioned above. For most users, SwOS is the right call.

The Verdict

Buy it if you need silent, affordable 100G L2 switching and understand the CPU limitations. Skip it if you need routing performance, have poor rack ventilation, or want zero cable compatibility headaches.

The CRS504-4XQ-IN is a brilliant tool with sharp edges. At 3.7/5, it’s a strong recommendation for the right buyer — just know exactly what you’re getting into before you pull the trigger.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.