Head-to-head
Gemini 3.5 Flash vs GLM 5.1
Compare Gemini 3.5 Flash and GLM 5.1 on the metrics that decide an agent workload.
| Metric | Gemini 3.5 Flash | GLM 5.1 |
|---|---|---|
| Provider | Google Gemini | Fireworks AI |
| Input / 1M | $1.50 | $1.40 |
| Output / 1M | $9.00 | $4.40 |
| Cache read / 1M | $0.15 (−90%) | $0.26 (−81%) |
| Reuse-adj @55% | $2.82 | $1.68 |
| Context | 1M | 203K |
| Cache capture | 85% | 83% |
| Warm TTFT | 150ms (−61%) | 130ms (−62%) |
| Quality index | 94 | 89 |
Teal marks the better value in each row. Reuse-adjusted assumes 55% prefix reuse and a 25% output share.
Pick Gemini 3.5 Flash when it scores higher on the composite quality index, it carries the larger 1M context window, it captures more of the available reuse.
Pick GLM 5.1 when it is cheaper once prefix reuse is priced in, it answers faster on warm cache hits, it is open-weights for on-prem and regulated lanes.
Gemini 3.5 Flash leads on quality while GLM 5.1 leads on reuse-adjusted cost. Send latency- and budget-sensitive volume to GLM 5.1 and reserve Gemini 3.5 Flash for the hard requests. Zumik's aliases route between them automatically under policy.
Frequently asked
Gemini 3.5 Flash vs GLM 5.1, answered.
Is Gemini 3.5 Flash or GLM 5.1 cheaper?
At 55% prefix reuse, Gemini 3.5 Flash blends to about $2.82 per 1M tokens and GLM 5.1 to about $1.68. GLM 5.1 is cheaper on that basis.
Which has the larger context window?
Gemini 3.5 Flash has the larger window: 1M vs 203K tokens.
Which captures more reuse?
Gemini 3.5 Flash shows higher measured cache capture (85% vs 83%) in the Zumik corpus.
Let an alias pick for you.
Route to whichever model wins under current policy automatically. Zumik resolves the alias to the best fit per request, so you never hard-code a loser.