Can You Run Gemma 4 on a iMac (32GB)?
Yes — best fit is Gemma 4 31B at Q4_0 (4-bit) (~17.4GB) ✅ Comfortable, using 27GB of usable memory on a 32GB iMac.
Every Gemma 4 model on this configuration
| Model | Best quant | Size | Status |
|---|---|---|---|
| Gemma 4 E2B | BF16 (16-bit) | ~8 GB | ✅ Comfortable |
| Gemma 4 E4B | BF16 (16-bit) | ~15 GB | ✅ Comfortable |
| Gemma 4 12B | SFP8 (8-bit) | ~13.4 GB | ✅ Comfortable |
| Gemma 4 26B A4B | Q4_0 (4-bit) | ~15.6 GB | ✅ Comfortable |
| Gemma 4 31B | Q4_0 (4-bit) | ~17.4 GB | ✅ Comfortable |
How we got this verdict
32 - 5 = 27GB usable (macOS and background processes reserve roughly 5 GB of unified memory).
31B lands on Q4_0 here, so grab the official QAT (quantization-aware training) checkpoint instead of a generic Q4_0 quant. Google shipped a full-quality QAT build for 31B at essentially the same ~19GB download size, with noticeably better output quality than a naive 4-bit quant. See the QAT guide for exact file names.
One tier down, at 24GB, the best fit drops to 12B (comfortable) instead.
Real-world notes for this configuration
32GB is the maximum memory Apple has offered on the 24-inch iMac — since the line has never used a Pro, Max, or Ultra chip, this is the practical ceiling for the whole product family, not just this specific generation.
- ⚠If your local-AI ambitions might grow past what 32GB comfortably covers, the iMac isn't the Mac to buy — a Mac Mini or Mac Studio offers a path to meaningfully more memory and bandwidth in a similar (or better, headless) form factor.
Try a different configuration
Best fit: Gemma 4 31B · Q4_0 (4-bit) · ~17.4 GB ✅ Comfortable
FAQ
Can a iMac (32GB) run the 31B flagship model?
Yes, comfortably — Gemma 4 31B fits at Q4_0 (4-bit) (~17.4GB), using 27GB of usable memory on this configuration.
What's the best Gemma 4 model for a iMac (32GB)?
Gemma 4 31B at Q4_0 (4-bit) (~17.4GB) is the best fit — it's the largest model that runs comfortably within the 27GB of usable memory here.
What if I have more or less memory than 32GB?
This is the top configuration in this family — every Gemma 4 model already fits at its best available quant. With less (e.g. 24GB), the best-fitting model gets smaller or tighter — see the iMac page.
Is there an iMac configuration above 32GB?
No — 32GB is the maximum Apple has offered on the 24-inch iMac, reflecting the line's use of only base-tier Apple Silicon chips.
Should I buy a maxed-out 32GB iMac for local AI, or a Mac Mini instead?
If you don't need the built-in display, a Mac Mini at the same or higher memory (including Pro-chip configurations above 24GB) generally gives more headroom and bandwidth for similar or less money — the iMac's value is the all-in-one display, not local-AI capacity.