Gemma 3 27B on Mac Studio M5 Max 64 GB

27.432B on 64 GB at 614 GB/s. Hardware details · Model details

Run locally →
Yes. Gemma 3 27B fits on Mac Studio M5 Max 64 GB at the recommended Q8_0 configuration, requiring approximately 33.4 GB at 8K context. Practical context capacity is 32K. Expected decode for the recommended configuration is ~14.9–21.4 t/s. Estimated
CompatibilityComfortable
Calculated fit
Yes
Calculated Uses under 80% of usable memory. Room for a long context and other work.
Recommended quantization
Q8_0
Calculated gguf
Memory required
33.4 GB
Calculated of 54.4 GB usable — 61%
Max practical context
32K
Calculated model supports 128K

Memory budget at 8K context

Model weights ⓘ
27.7 GB Calculated
KV cache ⓘ
3.9 GB Calculated
Runtime overhead ⓘ
1.8 GB Estimated
Total required
33.4 GB Calculated
Headroom ⓘ
21.0 GB Calculated
Highest-precision quantization that leaves headroom: uses 61% of usable memory at 8K context.
Unified memory: weights, KV cache and the OS share the same 64 GB pool. We assume 85% is addressable by the GPU, which matches a headless machine with the wired-memory limit raised.
Performance

Estimated performance · recommended Q8_0

Decode, prefill and TTFT below are estimates for Q8_0. We do not have a comparable Q8_0 measurement on this machine.

Estimated decode
~14.9–21.4 t/s
Estimated Q8_0; calculated range
Estimated prefill
~529–1100 t/s
Estimated Q8_0; calculated range
Estimated TTFT at 8K
~7.5–15.6 s
Estimated Q8_0; calculated range
Hardware load reference
118 W
Measured machine-level load; not this model run
How the estimate is calculated
  1. Decode: reading 27.4B active parameters at 8.50 bits/weight takes 54.17 ms at 614 GB/s x 88% achieved efficiency.
  2. Prefill: 120 TFLOPS (FP16) x 1.69 calibrated against measured prefill on this platform x 22% assumed model-FLOPs utilisation, divided by 2 x 27.4B parameters per token.

  • Prefill throughput is highly engine-dependent. Flash attention, batch size and quantized KV all move this number substantially, and for sparse mixture-of-experts models it is the least reliable figure we produce.
  • This is a calculated estimate, not a measurement. It assumes a single request, a short prompt, no speculative decoding and a warm model already resident in memory.

Estimator version estimator_v1. Stored with every estimated row so old estimates can be regenerated when the model improves.

Submit a benchmarkSubmissions stay pending until reviewed.
This model at other quantizations on this machine
QuantizationResidentDiskTotal neededUtilisationFitMax context
MLX 4-bit14.9 GB14.9 GB20.3 GB37%Comfortable64K
Q4_K_M16.0 GB16.0 GB21.3 GB39%Comfortable64K
Q5_K_M18.7 GB18.7 GB24.2 GB44%Comfortable64K
Q8_0recommended27.7 GB27.7 GB33.4 GB61%Comfortable32K
BF1651.1 GB51.1 GB57.5 GB106%Does not fit0
Cost of running Gemma 3 27B on this machineUnited States (federal) · C corporation · 8h/day
Monthly economic cost
$37
Calculated after tax
Codex/Claude Code
$100/mo
≈ $100/mo · local is $63 less
Net cash at purchase
$3,512
Calculated VAT not reclaimable
Total over 5 years
$2,213
Calculated after tax, after resale
Cost per USD/1M tokens
$16.06
Calculated 2.3M tokens/month

The $100 comparison uses the Codex Pro 5x / Claude Max 5x plans. A fixed planning conversion is used for USD. This compares monthly spend only: subscriptions have usage limits, local hardware has different capabilities and constraints, and taxes or regional pricing may change the charged amount. Prices checked 7 September 2026.

Purchase-price input: $3,512 in United States (federal), tax/VAT excluded · estimated · Apple Store NL (converted catalogue estimate). This is the localized purchase input; the after-tax economic cost is calculated separately below.

Monthly breakdown

Depreciation
2,459 over 5 years, straight-line to a 1,054 residual
$40.98
Electricity
5.3 kWh/month at 0.140/kWh
$0.74
Cost of capital
4.0%/yr on 2,283 average capital employed
$7.61
Monthly cost before tax$49.33
Electricity tax shield
Running costs are deductible business expenses
−$0.16
First-year expensing
§179 (100.0%)
−$12.29
Monthly economic cost after tax$36.88

Three different numbers, deliberately

Cash cost
$3,512
Money that leaves the bank account on day one, net of reclaimable VAT.
Accounting depreciation
$40.98/month
$2,459 written down over 5 years to a $1,054 residual.
After-tax economic cost
$36.88/month
Depreciation plus running costs plus cost of capital, less the tax those deductions save. This is the figure to compare between machines.
Assumptions and sources (verified 2026-09-07)
VAT rate
0% Official spec
VAT recoverable
0% Official spec
Federal C-corporation estimate at the flat 21% rate. Pass-through entities should use the sole-proprietor estimate as a rougher proxy.
Effective deduction rate
21.00% Calculated
Headline marginal rate 21.00%.
Depreciation
5 years, straight-line Assumption
Residual value
$1,054 (30%) Assumption
Extrapolated from the three-year curve.
Electricity
$0.140/kWh Assumption
Average power draw
30 W Calculated
Load 118 W for 20% of powered hours, idle 8 W for the rest — a machine that is on is not generating tokens the whole time.
Investment allowances
§179 100.0% Official spec
Worth $738 in total — first-year expensing that replaces later tax depreciation.
Cost of capital
$7.61/month Assumption
Assumes the machine generates tokens 20% of its 176 powered hours per month. Cost per token scales inversely with this number — halve the utilisation and the cost per token doubles.
Federal planning estimate only, not tax advice. State and local income tax, sales/use tax and incentives are excluded. It assumes 100% business use, a Section 179 election, enough business income to use it, and that the full annual limit remains available.
Efficiency metrics
Decode per $1,000 spent
5.2 t/s
Calculated purchase price only
Decode per $100/month
49.1 t/s
Calculated after-tax ownership cost
Tokens per joule
0.60
Calculated same as tokens/s per watt
USD per 1M output tokens
$16.06
Calculated at 20% utilisation
Local versus hosted APIs
Hosted modelUSD/1M outputBreak-evenAPI at your volumeVerdictComparison type
Qwen3.8 Flash
Alibaba Cloud
$0.4223.9M/mo$4API cheaperDifferent model
DeepSeek-V4.1 Flash
DeepSeek
$0.6020.5M/mo$4API cheaperDifferent model
DeepSeek-V4 Pro
DeepSeek
$1.985.1M/mo$17API cheaperDifferent model
DeepSeek V4 Pro (Together)
Together AI
$4.401.7M/mo$49Local cheaperDifferent model
GLM-5.3
Z.ai
$4.402.4M/mo$36About equalDifferent model
Claude Haiku 4.5
Anthropic
$5.002.8M/mo$30API cheaperDifferent model
Different-model comparison: the hosted model is not the model you would run locally. Treat this as a workload-quality trade-off, not a direct economic equivalence — the frontier model may complete a task in fewer tokens, or complete tasks the local model cannot. Break-even is the monthly output volume at which API spend equals the $37/month economic cost of owning this machine, assuming 8 input tokens per output token. Hosted prices are published in USD. This table is the canonical US default.