Local LLM configurator

Model

Quantization

Q4_K_M is the right trade-off for most uses. What is this?

Target speed

Around 10 tok/s reads comfortably; 30+ feels instant.

Platform

Advanced options8K tokens · KV cache f16

The defaults suit most uses. You can skip this section.

Context length

How much text the model keeps in memory. 8K is enough for chat; long documents need 32K or more. What is this?

KV cache type

Leave f16 if unsure. q8_0 roughly halves the conversation's memory, q4_0 nearly quarters it; the option must also be enabled in your app. What is this?

Compatible machines

What the model needs

gpt-oss-120b MXFP4 with a 8K context needs about 71.2 GB (up to 75.8 GB) of GPU or unified memory.

Compatible configurations for gpt-oss-120b MXFP4 · 8K context
	NVIDIAA100 80GBExcellent A100 80GB PCIe · 80 GB HBM2e 1,935 GB/s System RAM 64 GB Smallest configuration of this platform that runs the model entirely in fast memory.	AMD2 × Radeon PRO W7900Excellent Radeon PRO W7900 · 48 GB GDDR6 ECC 864 GB/s System RAM 64 GB Smallest configuration of this platform that runs the model entirely in fast memory.	Apple SiliconM2 Max · 96 GBCompatible MacBook Pro 14, MacBook Pro 16, Mac Studio 38 GPU · 400 GB/s Smallest configuration of this platform that runs the model entirely in fast memory.	Unified memory PCNVIDIA DGX Spark (GB10) · 128 GBExcellent GB10 Grace Blackwell 273 GB/s Smallest configuration of this platform that runs the model entirely in fast memory.	Highest estimated speedH100 PCIeExcellent H100 PCIe 80GB · 80 GB HBM2e 2,000 GB/s System RAM 64 GB Highest estimated generation speed among configurations that fit.
Memory for the model	78 GB	93 GB	72 GB	109 GBMost memory	78 GB
Estimated speed	170–472 tok/sestimate	66–135 tok/sestimate	32–44 tok/sestimate	41–57 tok/smeasured	175–488 tok/sestimateFastest
Power draw (GPU/board)	~300 W	~590 W	–	~240 WLowest power	~350 W
Price	No current offer	No current offer	No current offer	No current offer	No current offer
Confidence	medium	low	low	medium	medium

Leaders are marked per criterion; there is no overall winner. Speeds are estimates unless marked measured. Power is the GPU's rated board power (or the platform's, when known).

Suggested PC build

GPU: A100 80GB PCIe
Processor: Ryzen 7 9700X
RAM: 96 GB DDR5
Power supply: 600 W

The processor matters little when the model runs on the GPU; any current 8-core CPU is enough. PSU sized with 30% headroom for power spikes.

Compatibility checks: No compatibility problem detected between these parts.

Where to buy

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Radeon PRO W7900

Radeon PRO W7900 · 48 GB GDDR6 ECC · 864 GB/s

ExcellentRuns gpt-oss-120b MXFP4 entirely in memory

Price not available

Availability unknown

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NVIDIA DGX Spark (GB10)