# iAltair vs Opcodes

The clearest difference is in-app purchases: iAltair at none against Opcodes's 1. iAltair also leads on ratings volume (21 vs 6) and iOS requirement (15.4 vs 18.0). Opcodes's advantage is update cadence (every 8 days vs every 11 months). On price, rating, ads and monetization model there is nothing between them.

Both are free to download. Opcodes sells 1 one-off in-app purchase. iAltair asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.8 for iAltair against 4.8 for Opcodes. Both are backed by a comparable volume of ratings — 21 and 6 respectively.

iAltair ships an update every 11 months, Opcodes every 8 days. The most recent releases landed on August 27, 2026 and September 20, 2026 respectively.

## The numbers

| Metric | iAltair | Opcodes |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (21 ratings)](https://appshunter.io/ios/app/ialtair/id291182085/reviews) | [4.8 (6 ratings)](https://appshunter.io/ios/app/opcodes-retro-cpu-reference/id6760205834/reviews) |
| Number of ratings | **21** | 6 |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 11 months | **Every 8 days** |
| Monetization | Free | Free |
| Size | 10 MB | 58 MB |
| Requires iOS | **15.4** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Peter Schorn](https://appshunter.io/developer/291182088) | [John Kennedy](https://appshunter.io/developer/284943103) |

## What reviewers say

### iAltair

[App page](https://appshunter.io/ios/app/ialtair/id291182085)

Experience vintage computing with a simulation of the MITS Altair 8800. Explore old software like CP/M 2 and run programs such as Eliza using built-in BASIC. This self-contained system offers a unique glimpse into early computing history.

**Highlights:** MITS Altair 8800 simulation, CP/M 2 operating system support, Built-in BASIC interpreter, Run Eliza program, Self-contained system

**In-app purchases:** none


### Opcodes

[App page](https://appshunter.io/ios/app/opcodes-retro-cpu-reference/id6760205834)

This app provides a comprehensive reference for retro CPU opcodes, including detailed descriptions, assembly examples, and historical context. It covers eighteen iconic processors and offers features like search, sorting, and filtering for easy exploration of historical computing information.

**Highlights:** Opcode reference for 18 iconic processors, Detailed instruction descriptions, Hex, octal, decimal values, Flags affected, addressing modes, cycle counts, Assembly code examples, CPU history and pinout diagrams, Simple assembler/disassembler

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Buy Me a Coffee | $0.99 | one-time |


## Frequently asked questions

### Is iAltair free?

iAltair is free to download, with no in-app purchases.

### Is Opcodes free?

Opcodes is free to download, with in-app purchases available.

### Which has better reviews, iAltair or Opcodes?

iAltair and Opcodes are both rated 4.8 out of 5 on the App Store, from 21 and 6 ratings respectively.

### Do iAltair or Opcodes have ads?

Neither iAltair nor Opcodes shows ads.

### Which is updated more often, iAltair or Opcodes?

iAltair ships an update every 11 months, and Opcodes every 8 days. Most recently, iAltair was updated on August 27, 2026 and Opcodes on September 20, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*