GPT-5.3-Codex-Spark vs LFM2.5-1.2B-Instruct

Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.

GPT-5.3-Codex-Spark is clearly ahead on the aggregate, 87 to 30. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

GPT-5.3-Codex-Spark's sharpest advantage is in coding, where it averages 82.3 against 7.2. The single biggest benchmark swing on the page is SWE-bench Pro, 85 to 6.

GPT-5.3-Codex-Spark is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-1.2B-Instruct. That is roughly Infinityx on output cost alone. GPT-5.3-Codex-Spark is the reasoning model in the pair, while LFM2.5-1.2B-Instruct is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-5.3-Codex-Spark gives you the larger context window at 256K, compared with 32K for LFM2.5-1.2B-Instruct.

Quick Verdict

Pick GPT-5.3-Codex-Spark if you want the stronger benchmark profile. LFM2.5-1.2B-Instruct only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

85.6

LFM2.5-1.2B-Instruct

25.7

90
Terminal-Bench 2.0
22
82
BrowseComp
31
83
OSWorld-Verified
26

Coding

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

82.3

LFM2.5-1.2B-Instruct

7.2

91
HumanEval
14
80
SWE-bench Verified
9
80
LiveCodeBench
8
85
SWE-bench Pro
6

Multimodal & Grounded

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

88.3

LFM2.5-1.2B-Instruct

32.4

86
MMMU-Pro
27
91
OfficeQA Pro
39

Reasoning

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92.7

LFM2.5-1.2B-Instruct

32.1

94
SimpleQA
24
92
MuSR
22
97
BBH
59
91
LongBench v2
34
92
MRCRv2
37

Knowledge

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

78.3

LFM2.5-1.2B-Instruct

26

97
MMLU
26
95
GPQA
25
93
SuperGPQA
23
91
OpenBookQA
21
88
MMLU-Pro
50
42
HLE
1
88
FrontierScience
30

Instruction Following

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

92

LFM2.5-1.2B-Instruct

80

92
IFEval
80

Multilingual

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

90.8

LFM2.5-1.2B-Instruct

60.7

94
MGSM
62
89
MMLU-ProX
60

Mathematics

GPT-5.3-Codex-Spark

GPT-5.3-Codex-Spark

96.7

LFM2.5-1.2B-Instruct

37

98
AIME 2023
24
98
AIME 2024
26
97
AIME 2025
25
94
HMMT Feb 2023
20
96
HMMT Feb 2024
22
95
HMMT Feb 2025
21
95
BRUMO 2025
23
98
MATH-500
54

Frequently Asked Questions

Which is better, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark is ahead overall, 87 to 30. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 85 and 6.

Which is better for knowledge tasks, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for knowledge tasks in this comparison, averaging 78.3 versus 26. Inside this category, MMLU is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for coding in this comparison, averaging 82.3 versus 7.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for math in this comparison, averaging 96.7 versus 37. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for reasoning in this comparison, averaging 92.7 versus 32.1. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for agentic tasks in this comparison, averaging 85.6 versus 25.7. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for multimodal and grounded tasks in this comparison, averaging 88.3 versus 32.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for instruction following in this comparison, averaging 92 versus 80. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-5.3-Codex-Spark or LFM2.5-1.2B-Instruct?

GPT-5.3-Codex-Spark has the edge for multilingual tasks in this comparison, averaging 90.8 versus 60.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.

Last updated: March 12, 2026

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