Recovering 4.1 GiB of hidden RAM on NVIDIA DGX Spark with a 64 KiB kernel
marian_nmt · x · 2026-10-02
Marcin Junczys-Dowmunt published a full write-up, source code, and runbook for reclaiming 4.1 GiB of RAM that Linux hides from the NVIDIA DGX Spark's 128 GB unified memory. Two stacked tricks: (1) installing NVIDIA's official 64 KiB kernel cuts vmemmap struct page metadata by 16x, recovering 2.098 GiB (the 4 KiB kernel can be kept as a GRUB fallback); (2) reclaiming the 2,046 MiB display reservation on a headless GB10 adds another 2,046 MiB. Combined, this grows a GLM-5.3-Flash KV pool from 262,144 to 937,984 tokens (3.58x) per host. He notes prior community work covered each method separately, but not together.
Related event: Two tricks recover 4.1 GiB of hidden memory on DGX Spark(2 posts)→
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