Solar Pro 4 vs Gemini 3.8 Flash
Gemini 3.8 Flash comes out ahead, 63 to 55 on our weighted score, though Solar Pro 4 is 2.9× cheaper per token.
Upstage
Solar Pro 4
55/100- ECI—
- Price$0.30 / $1.20
- Context524K
- Our pick
GoogleGemini 3.8 Flash
63/100- ECI156.9
- Price$0.75 / $3.75
- Context1.05M
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Make it a three-way comparison.
Gemini 3.8 Flash is our pick
Gemini 3.8 Flash is the better all-round choice, scoring 63/100 against Solar Pro 4 (55). It leads on inputs & features and context window. Solar Pro 4 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceSolar Pro 4Solar Pro 4 $0.525 · Gemini 3.8 Flash $1.50 per 1M tokens (3:1 blend)
- Longest contextGemini 3.8 FlashGemini 3.8 Flash 1,048,576 · Solar Pro 4 524,288 tokens
- Widest inputsGemini 3.8 FlashSolar Pro 4: Text · Gemini 3.8 Flash: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Solar Pro 4 | Gemini 3.8 Flash |
|---|---|---|---|
| Price | 50% | 63 | 42 |
| Inputs & features | 30% | 45 | 100 |
| Context window | 20% | 49 | 61 |
| Overall | 100% | 55/100 | 63/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Solar Pro 4Upstage | Gemini 3.8 FlashGoogle |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | 156.9 |
| ECI rank | — | #15 of 148 |
| GPQA DiamondGraduate-level science questions | — | 95.4% |
| FrontierMath Tiers 1–3Research-level mathematics | — | 68.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | — | 98.9% |
| SimpleQA VerifiedShort factual questions | — | 69.7% |
| Price per million tokens | ||
| Input | $0.30 (best) | $0.75 |
| Output | $1.20 (best) | $3.75 |
| Cached input | $0.06 (best) | $0.075 |
| Blended (3:1) | $0.525 (best) | $1.50 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Upstage API | Official Google API |
| Limits | ||
| Context window | 524,288 tokens | 1,048,576 tokens (best) |
| Max output | 131,072 tokens (best) | 65,536 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | Yes |
| PDFs | No | Yes |
| Audio | No | Yes |
| Video | No | Yes |
| Reasoning | Yesminimal · low · medium · high · xhigh · max | Yeslow · medium · high |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | solar-pro4 | gemini-3.8-flash |
| API providers | 3 | 21 (best) |
| Released | Aug 6, 2026 | Sep 2, 2026 |
| Knowledge cutoff | Feb 2026 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Solar Pro 4$5.40
- Gemini 3.8 Flash$15.00
Which should you choose?
Which is better: Solar Pro 4 or Gemini 3.8 Flash?
Gemini 3.8 Flash is the better all-round choice, scoring 63/100 against Solar Pro 4 (55). It leads on inputs & features and context window. Solar Pro 4 wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Solar Pro 4 or Gemini 3.8 Flash?
Solar Pro 4 is cheaper at $0.30 input / $1.20 output per million tokens (official Upstage API price). Gemini 3.8 Flash costs $0.75 input / $3.75 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $0.525 per million tokens for Solar Pro 4 versus $1.50 for Gemini 3.8 Flash (2.9× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Solar Pro 4 has not been scored yet and Gemini 3.8 Flash has an ECI of 156.9.
Which is better for coding?
There are no published SWE-bench Verified results for Solar Pro 4 and Gemini 3.8 Flash yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3.8 Flash has the largest context window at 1,048,576 tokens, against 524,288 for Solar Pro 4. Maximum output per response: Solar Pro 4 up to 131,072, Gemini 3.8 Flash up to 65,536 tokens.
Which can read images, PDFs, audio or video?
Solar Pro 4 accepts text; Gemini 3.8 Flash accepts text, images, PDFs, audio and video. Gemini 3.8 Flash handles the widest range of inputs.
Are any of these open source?
No. Solar Pro 4 and Gemini 3.8 Flash are proprietary and only available through APIs and apps.
Which is newer?
Gemini 3.8 Flash is the newest, released Sep 2, 2026. Solar Pro 4 came out Aug 6, 2026. Knowledge cutoff: Solar Pro 4 Feb 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
