MemArena is a single-world memory benchmarkA standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.Full definition →: 50 simulated agents interacting for 15 days (10.3M dialog tokenThe chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.Full definition →) with co-generated ground truth across recall, reasoning and trustworthiness dimensions.
Memory-backend choice beats reader scaling for content accuracy: at Qwen3-0.6B, swapping Memobase for MemSearch gains +32.5/+19.2pp - more than scaling the reader model itself (+10.6/+6.8pp).
Permission-aware access fails universally: oracle retrieval leaks private information heavily while every other backend is too timid to disclose even permitted facts.
Memory-search latency is a fixed, moderate 7-87ms on an edge node - a small share of time-to-first-token for most reader-backend combinations, so latency is not the blocker.
Terms in this piece · Glossary
benchmark — A standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.
open weights — A model whose trained parameters are published for anyone to download and run — unlike API-only models you can access but never possess.
token — The chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.
Why it matters
If you're building on-device personal memory assistants, backend design choices matter more than swapping in a bigger model, and current permission-aware privacy access mechanisms are broken across the board—both are load-bearing facts for architecture decisions.
Key quotes
“Permission-aware access fails universally, with Oracle leaking heavily and other backends too timid to disclose.”
“Memory-backend choice matters more for content accuracy: At Qwen3-0.6B, Memobase-to-MemSearch gains +32.5/+19.2 pp, exceeding MemSearch reader scaling (+10.6/+6.8 pp).”