Sonnet's new Echo SE III T5 gives Macs three PCIe slots for $799.99, costing less than its larger desktop model, at the cost of no longer supporting full-length cards.
The compact enclosure lets Mac mini, Mac Studio, and MacBook Pro users add professional hardware their computers don't have internal slots for. It connects up to three PCIe cards through a single Thunderbolt cable for specialized audio, video, networking, and storage.
Sonnet introduced the larger Echo III T5 Desktop on October 14. The $1,199.99 enclosure supports PCIe cards up to 12.28 inches long and includes a 400W power supply, while the new Echo SE III T5 accommodates shorter cards up to 7.75 inches.
Both systems have the same advertised aggregate PCIe bandwidth, so the main differences are physical size, supported cards, and power provision. Sonnet also introduced a single-slot enclosure earlier in October for users who don't need room for multiple cards.
Each enclosure offers the same advertised 3,400 MB/s of aggregate PCIe bandwidth, but the larger model supports longer cards and has a more powerful internal power supply.
Three PCIe slots for professional hardware
The Echo SE III T5 has three PCIe 3.1 x8 slots that accept full-height, half-length+ cards. Users can install three single-width cards or one double-width card alongside a single-width card.
Compatible hardware includes video capture and transcoding cards, professional audio processors, 10Gb and 25Gb Ethernet adapters, SSD storage cards, and SAS host bus adapters. The enclosure also accepts compatible PCIe 4.0, 2.0, and 1.1 cards, although its slots operate at PCIe 3.1 speeds.
Sonnet rates the Echo SE III T5 at up to 3,400 MB/s of aggregate, bidirectional PCIe bandwidth when connected to a Thunderbolt 5 computer. The installed cards share the available bandwidth, so each slot doesn't get its own 3,400 MB/s.
The enclosure also works with supported Thunderbolt 4 and USB4 computers, although peak throughput depends on the host connection. Mac users need macOS 15 or later, and their PCIe cards must have compatible drivers.
The Echo SE III T5 has three PCIe 3.1 x8 slots that accept full-height, half-length+ cards.Physical fit doesn't guarantee compatibility, either. Sonnet designed the enclosure for non-GPU PCIe cards, and buyers should check their hardware's power requirements and driver support before purchasing.
Compact design with quiet cooling
The aluminum enclosure measures 6.5 inches wide, 11 inches deep, and 4.6 inches tall. At 3.7 pounds, it's small enough to move between workstations without the bulk of a full-size expansion system.
Cooling comes from a temperature-controlled Noctua fan that adjusts its speed as the installed cards heat up. Sonnet rates the fan at 17 dBA, quieter than a typical whisper at about 30 dBA, although the enclosure may be louder depending on the installed hardware and workload.
A 6-pin auxiliary PCIe power connector supports compatible cards requiring additional power. The enclosure also powers on and off automatically with the connected computer, so there's no separate power switch to manage.
Two Thunderbolt 5 ports handle external connections. One connects to the Mac, while the second supports another Thunderbolt or USB peripheral and provides up to 15W of power for compatible bus-powered devices.
Sonnet says users can also connect a 5K display through the second port using available bandwidth. The package includes a 0.8-meter Thunderbolt 5 cable and a ThunderLok connector lock to help prevent accidental disconnections.
Pricing & Availability
The Echo SE III T5, part number ECHO-SE3-T5, is available now from the Sonnet store and through B&H for $799.99. PCIe cards are sold separately, and the enclosure includes a two-year warranty.
There's one unusual detail with the first production units. Sonnet says they'll arrive with "Echo Express SE IIIe" printed on the front panel instead of the new product name. The labeling difference is cosmetic and won't affect Thunderbolt 5 functionality, performance, or warranty coverage.
