modelgrep

OpenAI: GPT-5.3-Codex vs xAI: Grok 4.3

xAI: Grok 4.3 wins on more metrics (6 of 9), but the right pick depends on what you optimize for — see the breakdown below.

MetricOpenAI: GPT-5.3-CodexxAI: Grok 4.3
Intelligence Index53.653.2
Coding Index53.141.0
GPQA Diamond92%90%
Design Arena Elo12291255
Speed (tokens/sec)5066
Latency3.5s746ms
Input price /M$1.75$1.25
Output price /M$14.00$2.50
Context window400K1M
CapabilitiesReasoningToolsJSONVisionReasoningToolsJSONVision