step-3.5-flash
stepfun-ai/step-3.5-flashstep-3.5-flash at Q4_K_M is exactly 119,937,953,440 bytes (111.70 GiB / 119.94 GB) — an effective 4.812 bits per weight, not the nominal 4. Its KV cache at 32K is 13.03 GiB, not the 45.00 GiB a flat formula predicts.
Shipped quantizations
| Quant | Size● | Exact bytes● | Effective bpw● | Tensors● | Publisher |
|---|---|---|---|---|---|
| IQ1_S | 38.47 GiB | 41,301,534,944 | 1.657 | — | bartowski |
| IQ1_M | 40.17 GiB | 43,127,491,808 | 1.730 | — | bartowski |
| IQ2_XXS | 44.74 GiB | 48,034,597,088 | 1.927 | — | bartowski |
| IQ2_XS2 shards | 51.40 GiB | 55,187,798,432 | 2.214 | — | bartowski |
| IQ2_S2 shards | 51.70 GiB | 55,513,426,368 | 2.227 | — | bartowski |
| IQ2_M2 shards | 58.63 GiB | 62,949,743,040 | 2.526 | — | bartowski |
| IQ2_M | 59.59 GiB | 63,980,443,584 | 2.567 | — | Ex0bit |
| Q2_K2 shards | 64.78 GiB | 69,553,669,568 | 2.791 | — | bartowski |
| Q2_K_L2 shards | 65.26 GiB | 70,069,253,568 | 2.811 | — | bartowski |
| IQ3_XXS2 shards | 72.82 GiB | 78,190,672,320 | 3.137 | — | bartowski |
| IQ3_XS3 shards | 75.46 GiB | 81,028,805,184 | 3.251 | — | bartowski |
| Q3_K_S3 shards | 80.06 GiB | 85,965,042,240 | 3.449 | — | bartowski |
| IQ3_M3 shards | 83.98 GiB | 90,168,226,336 | 3.618 | — | bartowski |
| Q3_K_M3 shards | 84.04 GiB | 90,232,418,848 | 3.620 | — | bartowski |
| Q3_K_L3 shards | 87.26 GiB | 93,692,326,464 | 3.759 | — | bartowski |
| Q3_K_L | 95.03 GiB | 102,042,463,936 | 4.094 | — | Ex0bit |
| IQ4_XS3 shards | 98.34 GiB | 105,591,741,984 | 4.237 | — | bartowski |
| IQ4_NL | 103.86 GiB | 111,520,582,336 | 4.475 | — | Ex0bit |
| IQ4_NL3 shards | 103.97 GiB | 111,641,955,904 | 4.479 | — | bartowski |
| Q4_03 shards | 105.60 GiB | 113,392,160,320 | 4.550 | — | bartowski |
| Q4_K_S3 shards | 107.70 GiB | 115,642,666,560 | 4.640 | — | bartowski |
| Q4_K | 110.56 GiB | 118,710,303,712 | 4.763 | — | ggml-org |
| Q4_K_M4 shards | 111.70 GiB | 119,937,953,440 | 4.812 | — | bartowski |
| Q4_K_L4 shards | 112.07 GiB | 120,329,797,280 | 4.828 | — | bartowski |
| Q4_14 shards | 115.15 GiB | 123,642,900,160 | 4.961 | — | bartowski |
| Q5_K_S4 shards | 126.55 GiB | 135,886,679,712 | 5.452 | — | bartowski |
| Q5_K_M4 shards | 130.58 GiB | 140,208,656,064 | 5.626 | — | bartowski |
| Q5_K_L4 shards | 130.88 GiB | 140,534,505,152 | 5.639 | — | bartowski |
| Q6_K5 shards | 150.81 GiB | 161,935,354,688 | 6.497 | — | bartowski |
| Q8_06 shards | 195.04 GiB | 209,417,870,976 | 8.403 | — | bartowski |
KV cache by context
| Context | KV cache (f16)● | Flat formula | Overstated by | Full / windowed / recurrent |
|---|---|---|---|---|
| 4,096 | 2.53 GiB | 5.63 GiB | 2.22× | 12 / 33 / 0 |
| 8,192 | 4.03 GiB | 11.25 GiB | 2.79× | 12 / 33 / 0 |
| 16,384 | 7.03 GiB | 22.50 GiB | 3.20× | 12 / 33 / 0 |
| 32,768 | 13.03 GiB | 45.00 GiB | 3.45× | 12 / 33 / 0 |
| 65,536 | 25.03 GiB | 90.00 GiB | 3.60× | 12 / 33 / 0 |
| 131,072 | 49.03 GiB | 180.00 GiB | 3.67× | 12 / 33 / 0 |
33 of 45 layers cache only a 512-token window rather than the full context, on a period of . Figures assume the default configuration; --swa-full disables the saving entirely.
Compare with
Will it run on your card?
Why other calculators give a different number
A parameters × bits ÷ 8 estimate puts Q4_K_M at roughly 104.45 GiB. The real file is 111.70 GiB, because a quantization is a mixture and some tensors are always kept at higher precision. The larger discrepancy is the cache: a flat formula gives 45.00 GiB at 32K context where the real figure is 13.03 GiB, because most of this model's layers cache a fixed window rather than the whole context.
Architecture
Questions people ask
- How much VRAM does step-3.5-flash need?
- Q4_K_M is exactly 119,937,953,440 bytes (111.70 GiB) in weights. Add the KV cache, which depends on your context length, plus roughly half a gigabyte of runtime overhead.
- How large is step-3.5-flash's KV cache?
- 13.03 GiB at 32K context with an f16 cache, computed per layer. Quantizing the cache to q8_0 roughly halves it, which is often the difference between a context length fitting and not.
- Which quantization of step-3.5-flash should I use?
- Q4_K_M is the usual default. Pick the largest quantization that fits your card at the context you actually need — the table above gives exact sizes for every one published.