GPT-6 Luna Max vs Grok 4.6 Xhigh: price, speed and benchmarks

This comparison puts OpenAI's GPT-6 Luna (Max) next to SpaceXAI's Grok 4.6 (Xhigh). Price separates them more than anything else; on a blended basis Grok 4.6 Xhigh costs 15 times as much as GPT-6 Luna Max. No hands-on testing went into this write-up; it summarises the recorded benchmark, price and speed data for both models.

Token pricing and a sample bill

GPT-6 Luna Max lists $0.10 per million input tokens and $0.50 per million output tokens; Grok 4.6 Xhigh lists $2.00 and $6.00. That makes GPT-6 Luna Max's output 92% cheaper.

A reference job of 1 million input tokens and 200,000 output tokens costs $0.20 with GPT-6 Luna Max and $3.20 with Grok 4.6 Xhigh, so GPT-6 Luna Max saves $3.00. For a support assistant answering 10,000 conversations of 2,000 input and 500 output tokens each, GPT-6 Luna Max would come in 94% lower: $4.50 for GPT-6 Luna Max against $70.00 for Grok 4.6 Xhigh.

Which is newer

The release dates are August 12, 2026 for Grok 4.6 Xhigh and September 22, 2026 for GPT-6 Luna Max, 41 days apart. They are effectively contemporaries.

Waiting time

Once a response is under way, GPT-6 Luna Max produces roughly 121 tokens per second against 62 tokens per second for Grok 4.6 Xhigh. GPT-6 Luna Max is ahead by 95% on throughput. Time to first token is 2.0 minutes for GPT-6 Luna Max and 47 seconds for Grok 4.6 Xhigh. The faster writer, GPT-6 Luna Max, gives away too much at the start to win on time: counting the first-token wait, Grok 4.6 Xhigh finishes first for any reply shorter than about 9,500 tokens. A first-token wait of that length suits background work better than live conversation.

Add the two numbers up for a 400-token reply and Grok 4.6 Xhigh finishes first: 2.1 minutes for GPT-6 Luna Max, 53 seconds for Grok 4.6 Xhigh.

Grok 4.6 Xhigh leads on the intelligence index

The catalogue puts GPT-6 Luna Max at 27.9 and Grok 4.6 Xhigh at 31.0 on its intelligence index. That is a clear margin for an index that averages many evaluations. In relative terms, Grok 4.6 Xhigh scores 11% higher.

Among 109 active scored models, GPT-6 Luna Max sits 62nd and Grok 4.6 Xhigh 49th.

There are no coding or math index scores for either model in the catalogue, which keeps this comparison at the aggregate level.

Cost per point of intelligence

Per point of intelligence index, GPT-6 Luna Max costs $0.0072 of blended price per million tokens and Grok 4.6 Xhigh $0.097. Grok 4.6 Xhigh costs 13 times as much per point, which is the price of its lead.