DeepSeek-V4 Flash on Mac Studio M3 Ultra 512 GB

304.18B (13B active) on 512 GB at 819 GB/s. Hardware details · Model details

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Yes. DeepSeek-V4 Flash fits on Mac Studio M3 Ultra 512 GB at the recommended Q8_0 configuration, requiring approximately 317.9 GB at 8K context. Practical context capacity is 1M. Expected decode for the recommended configuration is ~28.3–40.7 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
317.9 GB
Calculated of 435.2 GB usable — 73%
Max practical context
1M
Calculated model supports 1M

Memory budget at 8K context

Model weights ⓘ
307.0 GB Calculated
KV cache ⓘ
0.7 GB Calculated
Runtime overhead ⓘ
10.2 GB Estimated
Total required
317.9 GB Calculated
Headroom ⓘ
117.3 GB Calculated
Highest-precision quantization that leaves headroom: uses 73% of usable memory at 8K context.
Unified memory: weights, KV cache and the OS share the same 512 GB pool. We assume 85% is addressable by the GPU, which matches a headless machine with the wired-memory limit raised.
Mixture of experts: all 304.18B parameters must be resident in memory even though only ~13B are active per token. Memory follows total parameters; speed follows active parameters.
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
~28.3–40.7 t/s
Estimated Q8_0; calculated range
Estimated prefill
~111–231 t/s
Estimated Q8_0; calculated range
Estimated TTFT at 8K
~35.5–73.9 s
Estimated Q8_0; calculated range
Hardware load reference
205 W
Measured machine-level load; not this model run
How the estimate is calculated
  1. Decode: reading 13.0B active parameters at 8.50 bits/weight takes 23.81 ms at 819 GB/s x 71% achieved efficiency.
  2. MoE routing penalty of 15% applied: expert gathers are less bandwidth-efficient than a dense sweep.
  3. Prefill: 57 TFLOPS (FP16) x 1.72 calibrated against measured prefill on this platform x 22% assumed model-FLOPs utilisation, divided by 2 x 62.9B parameters per token.
  4. Prefill uses 62.9B effective parameters, not the 13B active in decode: a batch of hundreds of tokens routes across most of the expert pool.

  • MoE decode depends on how well the engine batches expert gathers; real results vary more than for dense models.
  • 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
DS4 Q2 (mixed)81.0 GB81.0 GB85.1 GB20%Comfortable1M
MLX 4-bit165.7 GB165.7 GB172.4 GB40%Comfortable1M
Q4_K_M176.9 GB176.9 GB183.9 GB42%Comfortable1M
Q5_K_M207.5 GB207.5 GB215.4 GB50%Comfortable1M
Q8_0recommended307.0 GB307.0 GB317.9 GB73%Comfortable1M
Cost of running DeepSeek-V4 Flash on this machineUnited States (federal) · C corporation · 8h/day
Monthly economic cost
$87
Calculated after tax
Codex/Claude Code
$100/mo
≈ $100/mo · local is $13 less
Net cash at purchase
$8,287
Calculated VAT not reclaimable
Total over 5 years
$5,198
Calculated after tax, after resale
Cost per USD/1M tokens
$19.84
Calculated 4.4M 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: $8,287 in United States (federal), tax/VAT excluded · estimated · Apple Refurbished / used market (converted catalogue estimate). This is the localized purchase input; the after-tax economic cost is calculated separately below.

Monthly breakdown

Depreciation
5,801 over 5 years, straight-line to a 2,486 residual
$96.68
Electricity
9.0 kWh/month at 0.140/kWh
$1.27
Cost of capital
4.0%/yr on 5,386 average capital employed
$17.95
Monthly cost before tax$115.90
Electricity tax shield
Running costs are deductible business expenses
−$0.27
First-year expensing
§179 (100.0%)
−$29.00
Monthly economic cost after tax$86.63

Three different numbers, deliberately

Cash cost
$8,287
Money that leaves the bank account on day one, net of reclaimable VAT.
Accounting depreciation
$96.68/month
$5,801 written down over 5 years to a $2,486 residual.
After-tax economic cost
$86.63/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
$2,486 (30%) Assumption
Extrapolated from the three-year curve.
Electricity
$0.140/kWh Assumption
Average power draw
51 W Calculated
Load 205 W for 20% of powered hours, idle 13 W for the rest — a machine that is on is not generating tokens the whole time.
Investment allowances
§179 100.0% Official spec
Worth $1,740 in total — first-year expensing that replaces later tax depreciation.
Cost of capital
$17.95/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
4.2 t/s
Calculated purchase price only
Decode per $100/month
39.8 t/s
Calculated after-tax ownership cost
Tokens per joule
0.67
Calculated same as tokens/s per watt
USD per 1M output tokens
$19.84
Calculated at 20% utilisation
Local versus hosted APIs
Hosted modelUSD/1M outputBreak-evenAPI at your volumeVerdictComparison type
Qwen3.8 Flash
Alibaba Cloud
$0.4256.3M/mo$7API cheaperDifferent model
DeepSeek-V4.1 Flash
DeepSeek
$0.6048.1M/mo$8API cheaperDifferent model
DeepSeek-V4 Pro
DeepSeek
$1.9811.9M/mo$32API cheaperDifferent model
DeepSeek V4 Pro (Together)
Together AI
$4.404.1M/mo$93About equalDifferent model
GLM-5.3
Z.ai
$4.405.6M/mo$68API cheaperDifferent model
Claude Haiku 4.5
Anthropic
$5.006.7M/mo$57API 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 $87/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.