MeRino designs sub-100M language models that run 4.9 times faster than OPT-350M

Researchers at the University of Central Florida and the University of Technology Sydney published MeRino on February 28, 2024, a method that draws up a transformer architecture to fit a given device’s limits on parameters, arithmetic and latency, instead of shrinking an existing model to fit. Their largest design, MeRino-64M, reaches the same 0.408 average accuracy across twelve zero-shot tasks as Meta’s OPT-350M while carrying 64M parameters against 331M. The authors time it at 114 ms against 559 ms for a 128-token input on an NVIDIA Jetson Nano, or 4.9 times faster.

The search scores a candidate architecture without ever training it. Each candidate shape, meaning how many blocks it has and how wide and how deep each block is, gets a single number that the authors compute from the dimensions of its attention and feedforward matrices and treat as a measure of how much information the network can represent, with a second term that penalises shapes which are deep and narrow, because those train badly. An evolutionary algorithm mutates block widths and depths for 100,000 rounds, discards everything that breaks the budget, keeps the highest-scoring survivors and returns the best one. A precomputed lookup table stands in for the matrix decomposition the score would otherwise need, and the authors put its average error at 0.03 percent.

Because the score is arithmetic over an architecture’s dimensions rather than a forward pass, the search runs on the target board itself. The paper puts one MeRino search at 0.05 hours and 0.75 Wh on the Jetson Nano’s CPU, against 1.2 hours and 300 Wh for the TE-NAS architecture search on an NVIDIA GTX 1080Ti. Every device measurement in the paper comes from that Jetson Nano developer board, taken at batch size 1 and sequence length 128 and averaged over 16 runs, and the authors report no measurements on phones or tablets. Training the designed models is separate and conventional work, at 600,000 steps on 8 NVIDIA H100 GPUs.

The same tables show MeRino-64M behind OPT-350M on language modelling, at 22.47 against 18.51 perplexity on WikiText-2 and 27.06 against 23.08 on Penn Treebank, where lower is better. The smallest design, MeRino-52M, matches Pythia-70M at 0.383 average zero-shot accuracy and 48 ms against 95 ms. The authors state that the weights and evaluation for Meta’s MobileLLM were not released when they submitted, so they do not compare against it, and they report that 8-bit weight quantisation leaves accuracy almost unchanged while 4-bit costs about 1 percent. The work was accepted at AAAI 2025 and the paper names no code release.