Gemini 3.8 Flash High vs GLM-5.3-Flash compared

Gemini 3.8 Flash High leads the intelligence index 30.8 to 27.8. Compare price, speed, latency and a clear verdict.

Metric	Gemini 3.8 Flash (High)	GLM-5.3-Flash
Intelligence Index	30.8	27.8
Input price (per 1M tokens)	$0.75	$0.15
Output price (per 1M tokens)	$3.75	$0.50
Output speed (tokens/s)	121	56
Time to first token	27s	1.6s
Release date	2026-09-02	2026-08-26

Metric

Gemini 3.8 Flash (High)

GLM-5.3-Flash

Intelligence Index

30.8

27.8

Input price (per 1M tokens)

$0.75

$0.15

Output price (per 1M tokens)

$3.75

$0.50

Output speed (tokens/s)

121

Time to first token

27s

1.6s

Release date

2026-09-02

2026-08-26

This comparison puts Google's Gemini 3.8 Flash (High) next to Z AI's GLM-5.3-Flash. The sharpest difference is price: GLM-5.3-Flash costs $0.50 per million output tokens, against $3.75 for Gemini 3.8 Flash High. Everything below is read from the benchmark, price and speed data in Franklin AI's catalogue; nothing here comes from a hands-on test.

Price per token

Gemini 3.8 Flash High lists $0.75 per million input tokens and $3.75 per million output tokens; GLM-5.3-Flash lists $0.15 and $0.50. For output tokens, Gemini 3.8 Flash High is 7.5 times the price of GLM-5.3-Flash.

For a sample workload of 1 million input tokens and 200,000 output tokens, Gemini 3.8 Flash High would cost $1.50 and GLM-5.3-Flash $0.25, a difference of $1.25. A bigger example, a month of coding-assistant traffic at 30 million input and 3 million output tokens, costs $33.75 on Gemini 3.8 Flash High and $6.00 on GLM-5.3-Flash: a gap of $27.75.

Generation gap

GLM-5.3-Flash came first, on August 26, 2026; Gemini 3.8 Flash High followed on September 2, 2026. They are effectively contemporaries.

Speed and latency

Gemini 3.8 Flash High generates about 121 tokens per second and GLM-5.3-Flash about 56 tokens per second. Gemini 3.8 Flash High is ahead by 117% on throughput. Before any text appears, Gemini 3.8 Flash High takes 27 seconds and GLM-5.3-Flash 1.6 seconds. So the two pull in opposite directions, with GLM-5.3-Flash quicker off the mark and Gemini 3.8 Flash High quicker once it gets going; the crossover is around 2,700 tokens.

Add the two numbers up for a 600-token reply and GLM-5.3-Flash finishes first: 32 seconds for Gemini 3.8 Flash High, 12 seconds for GLM-5.3-Flash.

Reasoning and overall scores

Gemini 3.8 Flash High records 30.8 on the intelligence index and GLM-5.3-Flash records 27.8. It is a meaningful gap rather than a rounding difference. In relative terms, Gemini 3.8 Flash High scores 11% higher.

Among 109 active scored models, Gemini 3.8 Flash High sits 50th and GLM-5.3-Flash 63rd.

Neither model has a separate coding or math index recorded yet, so those narrower comparisons will have to wait for more data.

Value for money

A blunt value measure, blended price over intelligence score, puts Gemini 3.8 Flash High at $0.049 and GLM-5.3-Flash at $0.0085 per point. GLM-5.3-Flash delivers each index point for 82% less; whether Gemini 3.8 Flash High's extra 3.0 points are worth the premium depends on how often your tasks need them.

Common questions about Gemini 3.8 Flash High and GLM-5.3-Flash

Is GLM-5.3-Flash better than Gemini 3.8 Flash High?

It depends on what you need: Gemini 3.8 Flash High scores higher on the intelligence index, 30.8 to 27.8; GLM-5.3-Flash is 84% cheaper on blended price; Gemini 3.8 Flash High streams output 2.2 times as fast; and GLM-5.3-Flash reaches its first token sooner.

Was this comparison tested by hand?

The figures are the recorded benchmark, price and speed data in Franklin AI's model catalogue. This page is written from that data automatically; neither model was tested by hand for it.

When were Gemini 3.8 Flash High and GLM-5.3-Flash released?

Gemini 3.8 Flash High is newer. It was released on September 2, 2026, 7 days after GLM-5.3-Flash (August 26, 2026).

Which model has lower latency?

Gemini 3.8 Flash High generates output faster, at 121 tokens per second against 56 tokens per second. GLM-5.3-Flash reaches its first token sooner (1.6 seconds against 27 seconds). Counting the first-token wait, GLM-5.3-Flash finishes short replies first and Gemini 3.8 Flash High pulls ahead beyond about 2,700 tokens.

Who makes Gemini 3.8 Flash High and GLM-5.3-Flash?

Gemini 3.8 Flash High is made by Google and GLM-5.3-Flash by Z AI. Gemini 3.8 Flash High was released on September 2, 2026 and GLM-5.3-Flash on August 26, 2026.

Final whistle

Short answer: GLM-5.3-Flash is the stronger all-round pick on this data, while Gemini 3.8 Flash High makes sense in narrower cases. Pick GLM-5.3-Flash if cost matters ($0.50 against $3.75 per million output tokens) and users are waiting on the first word. Pick Gemini 3.8 Flash High if you need the higher overall score (30.8 against 27.8) and your outputs often run past about 2,700 tokens.

Where the numbers come from

The scores, speed and prices in this comparison come from independent third-party model evaluations that Franklin AI syncs each day, and the article was written from a snapshot of them. For the latest results, open the Gemini 3.8 Flash (High) and GLM-5.3-Flash pages. The AI Benchmark methodology explains how that data is collected and shown.