Cheapest box to run gpt-oss-120b at Q5_K_M
OpenAI’s gpt-oss-120b is 117B parameters, 5.1B of them read per token. The number below is computed from that and each vendor’s published specs, not asserted. Switch the quant or the context and it recomputes in place.
gpt-oss-120b at Q5_K_M needs 85GB.
Cheapest Config that fits: Ascent GX10, GB10 Grace Blackwell, 128GB. Fits, 36GB headroom. Est. 37.8 tok/s.
Best offer today: $3,999.99 at Best Buy — in stock, checked 45 days ago.
Price history: 46 days recorded.
Offers — Ascent GX10, GB10 Grace Blackwell, 128GB, 1TB
- Best BuyRead on 28 Aug 2026 and not re-read since: Best Buy blocks our automated checks, so this number is old and we say so rather than imply it is current. It was $1,999 under ASUS's own store once ASUS raised its price in September.in stockchecked 45 days ago$3,999.99
- ASUSlist pricein stockchecked 35 minutes ago$5,999
- Mac mini, M6, 16GB$1,099Won't fit−72GB headroom
- Mac mini, M6, 24GB$1,299Won't fit−64GB headroom
- Mac mini, M6, 32GB$1,499Won't fit−56GB headroom
- Mac mini, M5 Pro, 24GB$1,699Won't fit−64GB headroom
- Mac mini, M5 Pro, 48GB$2,499Won't fit−41GB headroom
- Mac Studio, M5 Max, 36GB$2,499Won't fit−52GB headroom
- Mac mini, M5 Pro, 64GB$2,899Won't fit−26GB headroom
- GeForce RTX 5090, 32GB$2,999.99+hostWon't fit−54GB headroom
- Won't fit−26GB headroom
- Mac Studio, M5 Max, 48GB$3,099Won't fit−41GB headroom
- Mac Studio, M5 Max, 64GB$3,499Won't fit−26GB headroom
- Fits36GB headroomest. 37.8 tok/s
- Tight4GB headroomest. 113 tok/s
- Fits35GB headroomest. 75.5 tok/s
- Fits36GB headroomest. 37.8 tok/s
- Fits35GB headroomest. 84.9 tok/s
- Tight4GB headroomest. 166 tok/s
- Fits163GB headroomest. 113 tok/s
- Fits163GB headroomest. 166 tok/s
- Fits419GB headroomest. 166 tok/s
| Config | Memory | Price | Fit | Headroom | Est. speed |
|---|---|---|---|---|---|
| Mac mini, M6 | 16GB | $1,099 | Won't fit | −72GB | — |
| Mac mini, M6 | 24GB | $1,299 | Won't fit | −64GB | — |
| Mac mini, M6 | 32GB | $1,499 | Won't fit | −56GB | — |
| Mac mini, M5 Pro | 24GB | $1,699 | Won't fit | −64GB | — |
| Mac mini, M5 Pro | 48GB | $2,499 | Won't fit | −41GB | — |
| Mac Studio, M5 Max | 36GB | $2,499 | Won't fit | −52GB | — |
| Mac mini, M5 Pro | 64GB | $2,899 | Won't fit | −26GB | — |
| GeForce RTX 5090 | 32GB | $2,999.99+host | Won't fit | −54GB | — |
| Mac Studio, M4 Max, refurb | 64GB | $3,049 | Won't fit | −26GB | — |
| Mac Studio, M5 Max | 48GB | $3,099 | Won't fit | −41GB | — |
| Mac Studio, M5 Max | 64GB | $3,499 | Won't fit | −26GB | — |
| Ascent GX10, GB10 Grace Blackwell | 128GB | $3,999.99 | Fits | 36GB | 37.8 tok/s |
| Mac Studio, M3 Ultra, refurb | 96GB | $4,329 | Tight | 4GB | 113 tok/s |
| Mac Studio, M4 Max, refurb | 128GB | $4,409 | Fits | 35GB | 75.5 tok/s |
| DGX Spark, GB10 Grace Blackwell | 128GB | $4,699 | Fits | 36GB | 37.8 tok/s |
| Mac Studio, M5 Max | 128GB | $5,099 | Fits | 35GB | 84.9 tok/s |
| Mac Studio, M5 Ultra | 96GB | $5,499 | Tight | 4GB | 166 tok/s |
| Mac Studio, M3 Ultra, refurb | 256GB | $7,729 | Fits | 163GB | 113 tok/s |
| Mac Studio, M5 Ultra | 256GB | $9,499 | Fits | 163GB | 166 tok/s |
| Mac Studio, M5 Ultra | 512GB | — | Fits | 419GB | 166 tok/s |
GeForce RTX 5090 is a card, not a computer: every price shown for it is the cheapest listing we found plus $1,000 for the minimum host machine.
memory = 117B × 0.709 B/param (5.67 bits) + 0.074 GB/1K × 8K K/V + 1.2 GB runtime
speed = bandwidth × 0.5 ÷ (5.1B active × 0.709 B/param) = 3.6 GB read per token
usable = memory − operating system reserve (8% on a Mac, 6% on a DGX Spark, 4% on a card)
Bandwidth is the vendor’s published figure. Every speed is an estimate and says so. Methodology.
What else Ascent GX10 GB10 Grace Blackwell 128GB runs
- Qwen3-235B-A22BQ3_K_M, est. 12.7 tok/s
- MiniMax-M2Q3_K_M, est. 27.9 tok/s
- Mistral-Large-2411Q6_K, est. 1.8 tok/s
- gpt-oss-120bQ6_K, est. 32.6 tok/s
- Llama-4-Scout-17B-16EQ8_0, est. 7.6 tok/s
- Qwen3-Coder-NextQ8_0, est. 42.8 tok/s
Best quant that still fits at 8K context, largest model first. Full list on the Config page.
Bandwidth 273GB/s, usable memory 120GB of 128GB.