API cost decision in 10 seconds

NewXing4.0 29B A4B (free) vs Solar Pro 4

Pick Xing4.0 29B A4B (free) for lower cost; pick Solar Pro 4 only if the larger context window matters more.

Page updated: 2026-10-16T20:07:48Z Data confirmed: 2026-10-16T21:07:49Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Xing4.0 29B A4B (free) for lower cost; pick Solar Pro 4 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Xing4.0 29B A4B (free) is estimated at $0 vs $0.27 for Solar Pro 4, saving $0.27 (100% lower).

Cost-first pickXing4.0 29B A4B (free)

Context-first pickSolar Pro 4

Sample savings$0.27100%

10x traffic gap$2.7

Solar Pro 4 has more context, but Xing4.0 29B A4B (free) saves $0.27 on the standard workload. At 10x that traffic, the same price gap is about $2.7. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Xing4.0 29B A4B (free) stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Xing4.0 29B A4B (free)	Solar Pro 4
Input-heavy / RAG	5M input + 500K output	Xing4.0 29B A4B (free)	$0	$0.63
Balanced workload	1M input + 1M output	Xing4.0 29B A4B (free)	$0	$0.45
Output-heavy chatbot	1M input + 5M output	Xing4.0 29B A4B (free)	$0	$1.89

Cheaper input Xing4.0 29B A4B (free) $0 vs $0.09 / 1M

Xing4.0 29B A4B (free) is free for input tokens while Solar Pro 4 costs $0.09 per 1M tokens.

Cheaper output Xing4.0 29B A4B (free) $0 vs $0.36 / 1M

Xing4.0 29B A4B (free) is free for output tokens while Solar Pro 4 costs $0.36 per 1M tokens.

Larger context Solar Pro 4 262.14K vs 524.29K

Solar Pro 4 has 262.14K more context (2x larger).

Sample workload Xing4.0 29B A4B (free) $0 vs $0.27

Xing4.0 29B A4B (free) is free for the standard workload while the other model is estimated at $0.27.

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Xing4.0 29B A4B (free) Calculating… Estimated API cost

Solar Pro 4 Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Xing4.0 29B A4B (free) has the lower input price; Xing4.0 29B A4B (free) has the lower output price; Solar Pro 4 offers the larger context window. For the 1M input plus 500K output sample, Xing4.0 29B A4B (free) is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0 for Xing4.0 29B A4B (free) and $0.27 for Solar Pro 4.

Best Fit

Choose Xing4.0 29B A4B (free) when you care most about lower input-token price, and lower output-token price.

Choose Solar Pro 4 when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Xing4.0 29B A4B (free) is estimated at $0 vs $0.27 for Solar Pro 4, saving $0.27 (100% lower).
Xing4.0 29B A4B (free) is free for the standard workload while the other model is estimated at $0.27.
Xing4.0 29B A4B (free) is free for input tokens while Solar Pro 4 costs $0.09 per 1M tokens.
Xing4.0 29B A4B (free) is free for output tokens while Solar Pro 4 costs $0.36 per 1M tokens.
Solar Pro 4 has 262.14K more context (2x larger).

Head-to-Head Specs

Feature	NewXing4.0 29B A4B (free) (XingChen)	Solar Pro 4 (Upstage)
Input Price prompt tokens per 1M	$0	$0.09
Completion Price per 1M tokens	$0	$0.36
Sample Workload Cost 1M input + 500K output	$0	$0.27
Context Window	262.14K	524.29K
Release Date	2026-10-16	2026-08-10

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Xing4.0 29B A4B (free)	On the standard 1M input plus 500K output workload, Xing4.0 29B A4B (free) is estimated at $0 vs $0.27 for Solar Pro 4, saving $0.27 (100% lower).
High-volume input processing	Xing4.0 29B A4B (free)	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Xing4.0 29B A4B (free)	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Solar Pro 4	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Solar Mini 4 can replace Solar Pro 4 when lower sample workload cost matters most: $0.15.

Larger context near this budget

Llama 4 Scout offers 1.31M context with $0.25 sample workload cost.
MiMo-V2.6-Flash offers 1.05M context with $0.28 sample workload cost.
GPT-6 Luna Pro (batch) offers 1.05M context with $0.17 sample workload cost.
GPT-6 Luna (batch) offers 1.05M context with $0.17 sample workload cost.

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XingChen catalog

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Xing4.0 29B A4B (free)

Xing4.0-29B-A4B is an open-weight mixture-of-experts language model from China Telecom's AI team (TeleAI) and the successor to the TeleChat series. It has 29B total parameters with 4B active per token...

Solar Pro 4

Solar Pro 4 is Upstage's cost-efficient large language model, featuring a 524K context window. It is built for long-horizon tasks and agentic workflows, with strong capabilities in office productivity, document-intensive...