These are not the same size of amplifier: Naim CI-Uniti 102 has roughly 3.8x the power of Naim Uniti Atom. That is about 5.7dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | A | Naim CI-Uniti 102 has more power - 150W against 40W into 8 ohms. That is about 5.7dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Room size | depends | We rate Naim CI-Uniti 102 the better fit for a large room and a very large room, and Naim Uniti Atom for desk or near-field listening, a small room and a mid-size room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | B | Both decode on board, but only Naim Uniti Atom handles DSD. |
| Streaming | evenly matched | Only Naim CI-Uniti 102 has AirPlay 2. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | evenly matched | The same number of line-level inputs (1). |
| Room to grow | evenly matched | The same expansion options on both. |
| Headphones | depends | Only Naim Uniti Atom has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Naim CI-Uniti 102 is Class D and Naim Uniti Atom is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Naim Uniti Atom takes up about 13% less shelf area (781cm² against 900cm²). |
| Price | A | Naim CI-Uniti 102 costs less - $1,499 against $3,799 at list. |
| Watts per dollar | A | Naim CI-Uniti 102 is the cheaper watt - about $10 per watt against $95. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Naim CI-Uniti 102 B Naim Uniti Atom
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Naim CI-Uniti 102 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - Naim CI-Uniti 102 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 40 watts is already more than most people ever use, and the extra 110 watts would be headroom you pay for and never hear - we rate Naim CI-Uniti 102 poorly for near-field use for exactly that reason. Think about the whole system: the roughly $2,300 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.