Speakers are where the iPhone Duo gives up the most to the iPhone 18 Pro Max, and Max Tech, which went in worried about weight and heat, says so first. The channel's verdict splits by buyer: someone who works on the phone may not go back to a Pro, and someone who shoots with it should stay.
Max Tech's benchmark runs
| Test | iPhone Duo | iPhone 18 Pro Max |
|---|---|---|
| Geekbench 7 Metal | 62,752 | 61,572 |
| Steel Nomad Light, one run | 24.7 | 27.2 |
| 20-minute stress stability | 66.5% | 62.2% |
| Hottest spot afterward | 42°C | 43.4°C |
The stability score flatters the Duo. The Pro Max started 24 percent higher on its best loop, and once both phones were saturated with heat the gap was still 16 percent. For a phone this thin, the channel calls that better than expected. Geekbench single-core came out identical, and the Duo dimmed its screen within the first few minutes of the stress run.
Where the Duo holds its own
- Weight. The two are hard to tell apart in the hand, and Max Tech compares the finish to the old stainless steel Pros.
- Cover screen. Side navigation and a wider keyboard made typing faster and more accurate, though websites that aren't optimized show very little on it.
- Split screen. QuickBooks can sit beside a banking app, a setup that used to send Max Tech to a MacBook. Only one app can play audio at a time.
- Modem and storage. The C2 matched the Qualcomm modem in the 18 Pro Max on the same server, and both 512GB models posted near-identical read and write speeds.
Where the Pro Max stays ahead
- Speakers. They're far quieter, with thinner bass, and the video calls it a trip back five years.
- The matte inner screen. It cuts reflections and looks brighter on video, but dark scenes look like an LCD, and Max Tech would trade a more visible crease for a glossy panel.
- Face ID and the Action button. Touch ID missed three or four times during setup, and there's no Action button to map an assistant to.
- Cameras. The under-display selfie looks waxy, the 12MP cover camera trails the Pro Max's 18MP front camera, and 10x on the Duo is a crop of the main sensor against a real telephoto. No LiDAR shows in portrait cutouts, and there's no RAW mode. Flipping the phone to shoot selfies on the 48MP main camera fixes most of the gap.
Max Tech cites a leak that puts Face ID on the next Duo's cover screen and gives it an Action button, which would settle two of these complaints and part of the iPhone Duo 2 wish list with them. I'd still put the speakers first, since a 16 percent GPU deficit only shows up in a benchmark and the sound shows up in every game.
