PowerEmu is built on QEMU, which already knows how to pretend to be a Power Mac. On its own, though, it stops a long way short of usable. Here’s what changed.

Plain QEMU	PowerEmu
A dumb framebuffer. Mac OS X draws every window itself, on the CPU.	An emulated Radeon 9000 that Tiger’s own ATI drivers bind to, unmodified.
No 3D at all, so games and screen savers either crawl or refuse to launch.	3D commands go to Metal on your real GPU. Warcraft III runs around 30 fps on high.
Quartz Extreme stays off, because Tiger looks for a real card and doesn’t find one.	It finds one. The compositor turns on and windows move like they should.
The pointer smears trails across OpenGL windows.	The host draws the cursor, so it stays clean.
A short list of old resolutions, none of them the shape of a modern display.	Modes that match your panel, plus true full screen including the notch.
Audio crackles and cuts out constantly.	Paced in real time, which fixed the dropouts. Some distortion is still being chased.
Plug in a USB device at the wrong moment and the whole thing wedges.	The USB controller drops missed frames instead of livelocking. It keeps going.
Click another window and macOS quietly parks it on the efficiency cores.	It tells macOS it’s busy, so it keeps running at full tilt in the background.
Stock settings that suit PowerPC code badly, so everything is slower than it needs to be.	Retuned emulation internals. One guest benchmark went from 9–11 seconds to about 2.
No link to the host: no clipboard, no shared folders, no clock sync.	All three, plus a real Shut Down instead of yanking the virtual power cable.
A second Dock icon and no way to manage more than one machine.	One app, one icon, and a library of VMs with their own disks and settings.

Your Mac

An Apple silicon Mac. The renderer is Metal, so this is not optional

macOS

macOS 14 Sonoma or later — what the app is built against

Memory

Whatever you give the virtual Mac, 2 GB by default, on top of your own

Storage

Room for a guest disk. A working Tiger install runs to tens of gigabytes once you fill it

Video memory

64, 128 or 256 MB, your choice, inside the virtual Mac

Guest system

Mac OS X 10.4 Tiger, tested. Leopard is untested so far

You supply

A Tiger install disc or an existing disk image, and the ATI ROM images. None of that ships with PowerEmu

Price

Free. GPL-2.0-or-later, like QEMU underneath it

Graphics

• An emulated ATI Radeon 9000 (RV280/R200) — ppc-mac-gpu, with an MMIO register set, a PM4 command processor and ring buffer, a 2D engine (fills, blits, host data, clipping) and AGP/GART address translation. Mac OS X’s own ATI kexts bind to it unmodified.
• A Metal renderer for the R200 3D pipeline. Draw packets go straight to Metal: hardware T&L (model-view-projection, lighting, spot lights and attenuation, texture matrices, fog), viewport and scissor, R200 texture combiners, alpha test, blending done in-shader through framebuffer fetch, plane masks, depth and stencil. Textures in ARGB8888, RGBA/ABGR8888, RGB565, ARGB1555, ARGB4444, I8, AI88, DXT1/3/5 and YUV 4:2:2, resident in VRAM or fetched over AGP. It renders into VRAM through linear Metal texture views — no shadow copies.
• Quartz Extreme. The uni-north host bridge gets an AGP capability and a working GART, so Apple’s AppleMacRiscAGP drives the bus, the Radeon driver builds its AGP GART and reports AccelCaps = 1, and WindowServer switches on the OpenGL compositor.
• A hardware cursor. A patched QEMU VGA NDRV reports cursor support and hands the image and position to the GPU model, which draws it on the host — fixing the stale save-under that left cursor-shaped notches over OpenGL windows.
• Host-shaped display modes. The device’s EDID (Established Timings III) and the patched NDRV’s mode table add 1440×932, 1280×828, 1152×746 and 1680×1088, plus below-the-notch variants. Full-panel fullscreen covers the whole display including the notch strip.
• 64, 128 or 256 MB of VRAM, behind a 1 GB uni-north PCI window.

Sound, input and stability

• Screamer audio pulls DMA at the sample rate from a 1 ms virtual-clock timer into a 186 ms ring; the position register advances with it and a 40 ms jitter buffer fronts the host backend. A four-second 1 kHz capture went from 10–20 dropouts to zero.
• Seamless pointer via a USB tablet taking absolute positions; captured mode remains for games.
• OHCI bounds transfer descriptors per endpoint per frame and drops missed frames rather than replaying them, which used to livelock the emulator under host load.

Speed

• Host scheduling. An NSActivityUserInitiated | LatencyCritical assertion plus QOS_CLASS_USER_INTERACTIVE on the TCG vCPU threads stops App Nap exiling the emulator to the efficiency cores. A guest benchmark loop dropped from 9–11 s to 3.4 s on that change alone.
• TCG: a raised softmmu TLB floor (1024 entries) and a 64K-entry TB jump cache retired by a generation counter, so a flush stays O(1) — a game covers 100k+ translation blocks and every PowerPC blr is an indirect branch.
• target/ppc: lmw/stmw expanded inline instead of a helper that probe_accesses the range, and a host-FPU fast path for A-form arithmetic when FPSCR is RN with no enables and no NaNs.
• GPU batching: conflicting batches ordered on the GPU with shared events rather than waitUntilCompleted on the vCPU thread, hybrid fences, an AGP/GART page-to-host-pointer cache, and draw vertices bump-allocated from a recycled 8 MB buffer.
• Net result: benchmark loop 9–11 s → 1.95 s. Warcraft III went from 4–5 fps to around 30 fps on all-high settings at 1680×1050.

The app and the guest

• SwiftUI app driving QEMU over QMP. VMs are .poweremu packages; importing disks and ROMs uses APFS clones. The guest screen is drawn inside the app through a poweremu-display object over a Unix socket with shared memory and damage rectangles, so QEMU isn’t a second Dock icon.
• PowerEmu Tools — a guest agent for 10.4+ PPC, installed per user with no administrator password: clipboard both ways, shutdown and restart through loginwindow (kAEShutDown/kAERestart), and an optional root clock daemon that steps errors over 1 s and slews smaller ones with adjtime.
• Shared folders over a WebDAV server implementing enough of RFC 4918 for Tiger’s webdavfs, on a per-VM Unix socket so no TCP port is opened.
• Service Hub: a mail proxy (the guest authenticates locally; PowerEmu does implicit TLS or STARTTLS to iCloud, Gmail, Yahoo or Fastmail with an app password) and a Web Accelerator on 10.0.2.100:7780 doing TLS 1.3 and HTTP/2, WebP/AVIF/HEIC transcoding, image downscaling and 204s for trackers.
• Built on QEMU 10.0.2 as patched by UTM. GPL-2.0-or-later.

You could do all of this by hand in a browser. Here is what The Garden does instead.

Doing it yourself	The Garden
Tiger’s browser cannot complete a handshake with the site any more, so you need a modern machine just to fetch the file.	Bundled TLS, so the old Mac talks to the site directly.
You find out whether something runs by downloading it and trying.	A badge on every download, worked out for the Mac you are on.
Unpack a StuffIt archive, work out which of nine files is the program, drag it somewhere sensible.	One button: download, verify, unpack, install, in the right place.
Nothing tells you a newer version exists.	Updates are spotted and installed, with a count on the Dock icon.
Nothing records what you already have.	A library with real icons, and one click to open or remove.
Every page is a fresh download over a slow link.	Pages are cached and revalidated, and still readable offline.

Mac

Any PowerPC G3 or later, or any Intel Mac. One universal binary covers both

System

Mac OS X 10.4 Tiger or 10.5 Leopard

Memory

256 MB is fine. It was built with small machines in mind

Storage

Whatever your installs need, plus a little for cached pages

Internet

Any connection. Modern TLS is bundled in, so there’s nothing to configure and no helper Mac required

Plays well with

Mac OS 9 for the oldest titles, and PowerEmu if you’d rather do all this on a modern Mac

Version

0.3.6, alpha

Price

Free. MIT licensed

Reaching the site at all

• Bundled TLS. Every transfer runs through a statically linked libcurl 8 and OpenSSL 3. Tiger and Leopard’s own TLS stops at 1.0 and can no longer negotiate with the site, so the system stack is bypassed entirely.
• One thread, one curl multi handle. A thread per request costs too much on a 256 MB G3; a single handle reuses connections, DNS answers and TLS sessions.
• Persistent page cache with per-request TTLs (item pages 3 days, listings 6 h, the feed 1 h), revalidated with If-None-Match and If-Modified-Since, with offline fallback.
• PowerEmu Web Accelerator client. Inside a virtual Mac it is found at 10.0.2.100:7780; on a real Mac over Bonjour with a pairing code. Pages and images go through it; downloads, form posts and the search token always go direct, so a file’s MD5 and the session are never in doubt. A Tiger G3 item page: 0.95 s direct, 0.20 s through PowerEmu — the difference is the TLS handshake. Absent, nothing changes.
• A custom NSURLProtocol puts the system WebKit on the same stack, so a WebView can reach the site on Tiger and shares the app’s cookies.

Store, install and library

• Featured (New & Noteworthy from rss.xml), Apps and Games A–Z, Categories and Search. Item pages carry screenshots, the rating, reviews parsed from the site’s comments, and rows of More by author and Related.
• Compatibility badges computed per download against the host: native, Rosetta, Classic, or unsupported.
• Install pipeline: MD5 verification, disk images via hdiutil, archives through the bundled XADMaster (StuffIt, BinHex, MacBinary, Compact Pro, zip and the rest), applications to /Applications, Mac OS 9 software to Applications (Mac OS 9), packages handed to Installer. Multi-floppy sets, including headerless raw images via CRawDiskImage, are mounted and copied out.
• Launchable selection prefers the binary whose name matches the title and skips updaters, installers, read-mes and launchers; existing library entries are re-checked at launch.
• Updates compare version numbers when both file names carry one and upload dates when neither does. The Dock icon is drawn by hand for progress and the badge, since Tiger has no NSDockTile.

Build

• Universal ppc + i386, deployment target 10.4, built with Apple gcc-4.0 against the 10.4u SDK — Xcode 2.5 on Tiger or 3.1 on Leopard. PowerPC is -mcpu=G3 -mtune=G4; Intel is -march=prescott.
• MIT licensed. XADMaster and UniversalDetector are the unmodified Universal builds from The Unarchiver 3.11.1, under the LGPL-2.1.

Your Mac already has a browser, and there is a well-loved alternative in PowerFox. Here is where Captain Polliwog differs.

The browser your Mac came with	Captain Polliwog
TLS stops at 1.0, so most sites refuse the connection outright.	Bundled OpenSSL 3 and libcurl 8. The handshake completes.
An engine from 2010: missing icons, broken layouts, scripts that fail.	WebKit 604, from 2018, built from source for PowerPC.
JavaScript runs in an interpreter, because PowerPC never had a JIT.	A PowerPC baseline JIT, 1.5–3.5× the interpreter.
Slower than PowerFox on most of Speedometer.	0.345 against PowerFox’s 0.189, winning 18 suites of 20.
Ten tabs and the machine starts swapping.	Background tabs release their pages and reload on return.
Video is a still frame and a spinning beachball.	Handed to VLC or MPlayer, which can decode it.
IPv6 lookups stall about fifteen seconds on networks without it.	Both families tried at once, so the page just starts.

Mac

Any PowerPC G3 or later, or any Intel Mac. One universal binary covers both

System

Mac OS X 10.4 Tiger or 10.5 Leopard

Memory

256 MB will run it — current Wikipedia loads on a 500 MHz G3 in about 53 MB. A gigabyte makes a real difference once you open a few tabs

Storage

Room for the app and its page cache

Internet

Any connection. TLS is built in, so there’s nothing to set up

For video

VLC or MPlayer, if you want to hand videos off to something that can decode them

Plays well with

PowerEmu, if you’d rather browse from a virtual Mac

Version

0.3.4, alpha

Price

Free. MPL 2.0

Networking

• Its own TLS. Every request goes through a bundled OpenSSL 3.5, libcurl 8.22 and zlib. The system stack stops at TLS 1.0 and cannot reach most sites any more.
• Plain HTTP goes the same way. Tiger and Leopard try a site’s IPv6 address first and wait about fifteen seconds for it to fail on networks without IPv6; libcurl tries both at once.
• One thread through a single curl multi handle, browser-level connection limits, and a disk cache that lets a repeat visit skip the network entirely.
• PowerEmu Web Accelerator client, for when it runs inside a virtual Mac.
• Current Wikipedia and DuckDuckGo load on a 500 MHz PowerBook G3 with 256 MB of RAM, in about 53 MB of memory.

The engine

• WebKit 604.5.7 — Safari 11, 2018 — built from source for PowerPC. Cross-compiled on an Apple silicon Mac in a Linux VM with a PowerPC toolchain (about 40 minutes from clean) and packaged as frameworks the browser loads, following Leopard WebKit’s structure. Built through WebKit’s CMake Mac port rather than the Xcode projects Apple used.
• It has to be a fork. Upstream WebKit removed big-endian support on August 1, 2026 (commit 232cebab), so no future WebKit will ever compile for a PowerPC Mac. This one is frozen on a branch with fixes carried back by hand.

Speed

• A PowerPC baseline JIT for JavaScriptCore — something it has never had. An offlineasm PowerPC backend runs the LLInt as native code, with a new assembler and macro assembler for the JIT, and the big-endian work that goes with it: EncodedJSValue returned tag-first from C but payload-first from JS, tag-first JSValue arguments, call frame payloads at +4, and byte-reversed loads for typed arrays. 1.5–3.5× the interpreter on micro-benchmarks.
• Layout that doesn’t redo itself. RenderLayer::updateLayerPositions used to walk every layer in the page after every layout. Each RenderElement now carries a four-bit generation number in spare bitfield room, marked up the ancestor chain by anything that moved and expiring on its own as the view advances the generation; the walk skips subtrees that didn’t change. Checked pixel for pixel against a full re-render via CGWindowListCreateImage. TodoMVC-Svelte-Complex-DOM: 3532 ms → 1277 ms.
• Speedometer 3.1 on a PowerBook G4: 0.259 → 0.345, against PowerFox 26.4’s 0.189. Eighteen of twenty suites now beat PowerFox; the two left are Charts-chartjs (Core Graphics path rasterization) and TodoMVC-ES5 (relayout boundaries).

What it supports

• Platform: flexbox and grid with gap, :has(), :focus-visible, unprefixed position: sticky, cascade layers, range media queries, :is()/:where(), logical properties, constructable style sheets; ES2017+ — classes and private members, async/await, generators and async generators, modules and import maps, BigInt; fetch, Web Timing, WebGL through ANGLE, WOFF2 via OTS, and full ICU with all 683 locales.
• The browser’s own code is under the MPL 2.0.