Is LFM2.5-350M or Qwen3-1.7B smaller?

LFM2.5-350M is smaller at Q4_K_M: 0.21 GiB against 1.03 GiB.

Which uses less memory at long context?

LFM2.5-350M — its KV cache at 32K context is 9.3x smaller, because of how its attention layers cache.

Model comparison

LFM2.5-350M vs Qwen3-1.7B

At Q4_K_M, LFM2.5-350M is the smaller download — 228,332,128 bytes against 1,107,409,472. At long context the gap widens: LFM2.5-350M's KV cache at 32K is 9.3× smaller, which usually matters more than the difference in weights.

From the file· summed bytes, KV per layer

Side by side

	LFM2.5-350M	Qwen3-1.7B
Parameters	354M	2.0B
Architecture	lfm2	qwen3
Layers	16	28
Native context	128,000	40,960
Mixture of experts	no	no
Quantizations published	13	48
Smallest quantization	0.20 GiB	0.50 GiB
Q4_K_M	0.21 GiB	1.03 GiB
Licence	other	—

KV cache by context

the term that decides long-context viability

Context	LFM2.5-350M	Qwen3-1.7B	Ratio
4,096	0.05 GiB	0.44 GiB	9.33×
8,192	0.09 GiB	0.88 GiB	9.33×
16,384	0.19 GiB	1.75 GiB	9.33×
32,768	0.38 GiB	3.50 GiB	9.33×
65,536	0.75 GiB	7.00 GiB	9.33×
131,072	1.50 GiB	14.00 GiB	9.33×