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xAI vs Inception
xAI sells closed Grok models with live X data. Inception sells closed diffusion models built for output speed.
By The Subconscious Team · Updated
xAI vs Inception: key differences
xAI's Grok 4.7 has 500K context at $2 in and $6 out, with Grok 4.6 measured at about 54 tokens per second, with older 4.20 and 4.3 models keeping 1M context. Prompts past 200K tokens bill at double. Native web and X search tools pull in live data. Inception sells closed Mercury diffusion models that refine a block of tokens in parallel instead of one at a time. Mercury 2.5 is a reasoning model with tool use and 260K context at $0.20 in and $0.75 out per million tokens; Inception reports over 1,100 tokens per second, and Artificial Analysis measures about 640.
Choose xAI for stronger reasoning and real-time social data. Choose Inception when speed and price matter more than top-end quality, as in autocomplete, voice agents and high-volume extraction.
What xAI and Inception do
xAI
xAI sells the Grok models through its own API. SpaceX acquired it in February 2026, and its docs now use the SpaceXAI name. Grok 4.7, released September 21, 2026, is the current flagship, pitched for coding, agentic tasks and knowledge work. It has a 500K context window and costs $2 in and $6 out per million tokens under 200K prompt tokens. Older Grok 4.20 and 4.3 models keep a 1M window at $1.25 in and $2.50 out, which is aggressive for that capability class.
Example models: Grok 4.7, Grok 4.20
Full xAI profile
Inception
Inception builds diffusion large language models (dLLMs). Every other LLM on this list generates text one token at a time; Inception's Mercury models start from a rough draft of a whole block and refine it over a few passes, producing many tokens in parallel. That ties speed less to output length and lets the models run fast on ordinary NVIDIA GPUs rather than custom chips. The company was founded by professors from Stanford, UCLA and Cornell behind core work on diffusion, Flash Attention and DPO, and is led by Stanford's Stefano Ermon. It raised a $50M seed in November 2025 led by Menlo Ventures, with Mayfield, M12, NVentures, Snowflake and Databricks, plus Andrew Ng and Andrej Karpathy as angels.
Example models: Mercury 2.5, Mercury 2
Full Inception profileShould you choose xAI or Inception?
xAI vs Inception at a glance
| Attribute | xAI |  Inception |
|---|---|---|
| Model access | Closed | Closed weights (Mercury dLLMs) |
| Flagship models | Grok 4.7, Grok 4.20, grok-build | Mercury 2.5, Mercury 2 |
| Speed | ~54 tok/s on Grok 4.6 | 1,100+ tok/s (vendor); ~640 measured |
| Price | $2 in, $6 out (Grok 4.7); 2x past 200K | $0.20 in, $0.75 out (Mercury 2.5) |
| Customization | Unknown | Fine-tuning on request |
| Deployment | First-party API | Serverless API, Bedrock, Azure, private |
| Long context | 500K (4.7), 1M (4.20, 4.3) | 260K |
Frequently asked questions
What is the difference between xAI and Inception?
xAI sells closed Grok models with live X data. Inception sells closed diffusion models built for output speed.
When should I choose xAI over Inception?
Live X data in answers; Up to 1M context on older models; grok-build for coding.
When should I choose Inception over xAI?
Very fast output on standard GPUs; Cheap reasoning with tool use and 260K context; Buying through AWS Bedrock or Azure.
Is xAI or Inception cheaper?
xAI: $2 in, $6 out (Grok 4.7); 2x past 200K. Inception: $0.20 in, $0.75 out (Mercury 2.5). The cheaper choice depends on the model and workload.
Which has more context, xAI or Inception?
xAI: 500K (4.7), 1M (4.20, 4.3). Inception: 260K.
Related comparisons
Running long-horizon agents?
If your agents run past 200K tokens, compare both against Subconscious. Our inference stack treats a long-horizon trace as the primary workload, so speed, cost, and accuracy hold up deep into the trace.