Accuracy is not compatibility: two Evo 2 checkpoints hinge on one FP8 matrix multiplication
Authors: Xun Ding (Independent researcher), Ziyuan Qin (Emory University)
Abstract
FP8 formats specify how values are stored, not how products are summed; this gap can break checkpoints. Evo 2, a DNA language model, documents a Hopper FP8 requirement for its 1B and 40B checkpoints. On two Blackwell (sm_120) GPUs both fail the developers' forward test (the 7B passes); on an RTX 5070 Ti the 40B's next-base accuracy is 25.7%, near guessing. Greater accuracy breaks them, as BioNeMo saw for the 40B on Hopper: natively, 99.996% of one projection's outputs are correctly rounded (H100: about 30%), and fp32 accumulation of the same operands fails. Our H100 FP8 GEMM emulator, mmaemu (bit-exact on captured 1B projections), localises the dependence to the 1B's first projection (of 21), where exact sums fail but pass when shrunk by the H100's 1.4% (measured in-sample), not 2.1%. The 40B fails with only its first projection native. Emulating only that projection, weights unchanged, raises 40B BRCA1 variant-classification AUROC from 0.434 to 0.869 (H100: 0.868) on the RTX 5070 Ti, despite a narrow forward-test miss, and 0.481 to 0.867 on an RTX PRO 6000. We tested one model family but not training origin; releases should specify reference arithmetic.
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Demystifying Numerical Instability in LLM Inference: Achieving Reproducible Inference for Mission-Critical Tasks with HEALZhenting Zhu, Lucas Thai, Shan Yu et al. · 2026 · arXiv.org · preprint, not peer reviewed · cited 3 times · Not summarized yet
HEAL traces divergent LLM outputs across GPUs to truncation at kernel boundaries, while this paper localizes checkpoint failures to FP8 accumulation arithmetic.
Abstract
As Large Language Models (LLMs) deploy into mission-critical domains (e.g., finance, medicine, and law), output reproducibility has become a strict system requirement. While practitioners use greedy decoding to eliminate algorithmic stochasticity, empirical deployments with 16-bit precisions still exhibit catastrophic output divergence across heterogeneous GPUs. Through SASS-level profiling, we reveal that this inconsistency is fundamentally driven by truncation errors introduced during downcasting at kernel boundaries. However, achieving reproducibility via a global FP32 pipeline incurs prohibitive system penalties: bypassing 16-bit hardware accelerators hurts compute efficiency, while upca…
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Bit-Accurate Modeling of GPU Matrix Multiply-Accumulate Units: Demystifying Numerical Discrepancy and AccuracyPeichen Xie, Shuotao Xu, Yang Wang et al. · 2025 · cited 4 times · Not summarized yet
This paper models GPU matrix multiply-accumulate arithmetic to explain numerical discrepancies, providing a modeling precedent for the Evo 2 paper’s arithmetic investigation.
Abstract
Modern AI accelerators rely on matrix multiply-accumulate units (MMAUs), such as NVIDIA Tensor Cores and AMD Matrix Cores, to accelerate deep neural network workloads. MMAUs expose only instruction-level or API-level interfaces of matrix multiply-accumulate (MMA) operations, while leaving internal floating-point arithmetic behavior undocumented. Consequently, MMAUs across vendors and architectural generations often produce numerical discrepancies for identical inputs, and sometimes exhibit reduced numerical accuracy that can cause training instability. Diagnosing and understanding the root causes of these effects is challenging without white-box models of their arithmetic behavior. This pape…
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CurveFP: Co-Designing Numerical Representation and Product Arithmetic for Language ModelsYe Qiao · 2026 · Not summarized yet
CurveFP redesigns low-precision representations and product arithmetic for language models, whereas this paper diagnoses compatibility failures in fixed FP8 checkpoints.
Abstract
Low-precision formats usually optimize scalar fidelity while inheriting conventional product arithmetic. We introduce CurveFP, a block-scaled family that distributes magnitudes across interleaved logarithmic curves. Uniform curve indices make every nonzero product an exact sign and integer-index update, while a rational radix exposes the finite phase schedule required for accumulation. We instantiate the algebra as CurveFP8 E4C3/E5C2 for training and CurveFP7 E3C3 for compact inference. On four 7B-9B models, CurveFP7 beats tensorwise FP8 perplexity with one fewer element bit and stays within 1.32% of native quality. CurveFP8 lowers error in all 36 paired training-GEMM comparisons. Across thr…
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Spec Sheets Are Not Kernels: An ISA- and Source-Level Audit of INT8 Availability on NVIDIA Blackwell UltraTeng-Ruei Chen · 2026 · cited 2 times · Not summarized yet
This audit examines Blackwell’s INT8 hardware and software support, while the Evo 2 paper tests how Blackwell FP8 arithmetic affects model compatibility.
Abstract
NVIDIA's published specifications give the Blackwell Ultra GPU (B300) a dense-compute ratio of roughly 30:1 between FP8 and INT8 tensor-core throughput; its predecessors, H200 and B200, both provide 1:1. We audit what this deprioritization means in practice by tracing INT8 W8A8 support through four layers of the stack: the published specifications, the PTX ISA, NVIDIA's CUTLASS kernel library, and the two major open-source LLM serving engines (vLLM and SGLang). We find a consistent, layered withdrawal: (i) the PTX ISA never exposes the fifth-generation tensor-core integer path (tcgen05.mma with .kind::i8) on sm_103a, even though the same PTX revision extends the FP4 kinds to that target, lea…
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Hawkeye: Reproducing GPU-Level Non-DeterminismErez Badash, Dan Boneh, Ilan Komargodski et al. · 2026 · arXiv.org · preprint, not peer reviewed · cited 3 times · Not summarized yet
Hawkeye reproduces GPU matrix-multiplication operations on CPUs, sharing the Evo 2 paper’s focus on reproducing GPU arithmetic behavior.
Abstract
We present Hawkeye, a system for analyzing and reproducing GPU-level arithmetic operations. Using our framework, anyone can re-execute on a CPU the exact matrix multiplication operations underlying a machine learning model training or inference workflow that was executed on an NVIDIA GPU, without any precision loss. This is in stark contrast to prior approaches to verifiable machine learning, which either introduce significant computation overhead to the original model owner, or suffer from non-robustness and quality degradation. The main technical contribution of Hawkeye is a systematic sequence of carefully crafted tests that study rounding direction, subnormal number handling, and order o…
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Reference Traces for Auditing Invisible Weight Updates and Guiding Exact-Budget ProtectionZekai Shang · 2026 · arXiv.org · preprint, not peer reviewed · Not summarized yet
This paper audits low-precision optimizer write-back against high-precision traces, rather than inference-time FP8 accumulation in fixed checkpoints.
Abstract
Direct low-precision write-back can erase nonzero optimizer proposals. We ask what a high-precision reference trace establishes before a low-precision run. The exact target-code event is auditable coordinatewise on a realized target trajectory; pre-run aggregate projection also assumes the reference remains a useful counterfactual. In a controlled two-layer grid, 55/72 cells have measured and predicted post-initialization crossings: times span $384\times$, 52/55 are within 15\%, and 4/72 differ in category. Matched decoder experiments show stochastic rather than nearest write-back recovers most of the loss gap. A prospective analytic-grid E4M3 audit reuses one fp32 trace across three unseen …
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Bridging Consumer and Enterprise: Benchmarking LLaMA, Qwen, and GPT Models on Diverse HardwareF. Khan, Shoaib Mustafa Khan · 2026 · International Conference on Multimodal Interaction · Not summarized yet
This benchmark compares LLM performance across hardware platforms, while the Evo 2 paper studies checkpoint accuracy and compatibility across GPUs.
Abstract
The increase of large language models (LLMs) such as Qwen, LLaMA, Mistral, and GPT variants has intensified the need for systematic benchmarking across heterogeneous hardware platforms. This paper evaluates NVIDIA A100 and RTX 3090 GPUs, AMD RX 580 and RX 7600 XT GPUs, and an Intel i5-14400F CPU on a diverse suite of open-source LLMs, including Mistral-7B, LLaMA-2 (7B, 13B), LLaMA-3.x (3B–11B), CodeLLaMA, Qwen1.5/2/2.5 (1.8B–14B), and legacy GPT models (GPT-2, GPT-Neo, GPT-J, GPT-NeoX-20B). Performance was assessed in terms of sustained TFLOPs, throughput in tokens per second (TPS), and memory/power efficiency. Results show that smaller Qwen models peaked at 276 TPS (A100), the RTX 3090 domi…
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DeepGEMM: Accelerated Ultra Low-Precision Inference on CPU Architectures using Lookup TablesDarshan C. Ganji, Saad Ashfaq, Ehsan Saboori et al. · 2023 · Machine Learning · cited 12 times · AI summary available
DeepGEMM accelerates ultra-low-precision inference on CPUs using lookup tables, unlike the Evo 2 paper’s study of FP8 arithmetic on GPUs.
Abstract
A lot of recent progress has been made in ultra low-bit quantization, promising significant improvements in latency, memory footprint and energy consumption on edge devices. Quantization methods such as Learned Step Size Quantization can achieve model accuracy that is comparable to full-precision floating-point baselines even with sub-byte quantization. However, it is extremely challenging to deploy these ultra low-bit quantized models on mainstream CPU devices because commodity SIMD (Single Instruction, Multiple Data) hardware typically supports no less than 8-bit precision. To overcome this limitation, we propose DeepGEMM, a lookup table based approach for the execution of ultra low-precis…
Prior work it builds on
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Mixed Precision Block Fused Multiply-Add: Error Analysis and Application to GPU Tensor CoresPierre Blanchard, N. Higham, Florent Lopez et al. · 2020 · SIAM Journal on Scientific Computing · cited 71 times · Not summarized yet
This work analyzes errors in mixed-precision fused multiply-add on GPU tensor cores, relevant to the Evo 2 paper’s investigation of accumulation arithmetic.
Abstract
Computing units that carry out a fused multiply-add (FMA) operation with matrix arguments, referred to as tensor units by some vendors, have great potential for use in scientific computing. However...
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Accurate Models of NVIDIA Tensor CoresFaizan A. Khattak, M. Mikaitis · 2025 · ACM Transactions on Architecture and Code Optimization (TACO) · cited 8 times · Not summarized yet
This work models NVIDIA tensor-core matrix multiplication and its numerical behavior, informing the Evo 2 paper’s analysis of GPU arithmetic differences.
Abstract
Matrix multiplication is a fundamental operation in both training of neural networks and inference. To accelerate matrix multiplication, Graphical Processing Units (GPUs) provide it implemented in hardware. Due to the increased throughput over the software-based matrix multiplication, the multipliers are increasingly used outside AI, to accelerate various applications in scientific computing. However, matrix multipliers targeted at AI are at present not compliant with IEEE 754 floating-point arithmetic behaviour, with different vendors offering different numerical features. This leads to non-reproducible results across different generations of GPU architectures, at the matrix multiply-accumu…
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Numerical behavior of NVIDIA tensor coresMassimiliano Fasi, N. Higham, M. Mikaitis et al. · 2021 · PeerJ Computer Science · cited 78 times · Not summarized yet
This study experimentally characterizes NVIDIA tensor-core arithmetic across GPU generations, groundwork for investigating checkpoint sensitivity to accumulation behavior.
Abstract
We explore the floating-point arithmetic implemented in the NVIDIA tensor cores, which are hardware accelerators for mixed-precision matrix multiplication available on the Volta, Turing, and Ampere microarchitectures. Using Volta V100, Turing T4, and Ampere A100 graphics cards, we determine what precision is used for the intermediate results, whether subnormal numbers are supported, what rounding mode is used, in which order the operations underlying the matrix multiplication are performed, and whether partial sums are normalized. These aspects are not documented by NVIDIA, and we gain insight by running carefully designed numerical experiments on these hardware units. Knowing the answers to…
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Accurate classification of BRCA1 variants with saturation genome editingGregory M. Findlay, R. Daza, B. Martin et al. · 2018 · Nature · cited 792 times · Not summarized yet
This study provides functional classifications of BRCA1 variants, which the Evo 2 paper uses to evaluate variant-classification performance.
Abstract
Variants of uncertain significance fundamentally limit the clinical utility of genetic information. The challenge they pose is epitomized by BRCA1, a tumour suppressor gene in which germline loss-of-function variants predispose women to breast and ovarian cancer. Although BRCA1 has been sequenced in millions of women, the risk associated with most newly observed variants cannot be definitively assigned. Here we use saturation genome editing to assay 96.5% of all possible single-nucleotide variants (SNVs) in 13 exons that encode functionally critical domains of BRCA1. Functional effects for nearly 4,000 SNVs are bimodally distributed and almost perfectly concordant with established assessment…
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The pitfalls of verifying floating-point computationsDavid Monniaux · 2007 · TOPL · cited 247 times · Not summarized yet
This work explains how floating-point computation semantics vary with implementation choices, a broader basis for the Evo 2 paper’s arithmetic-compatibility analysis.
Abstract
Current critical systems often use a lot of floating-point computations, and thus the testing or static analysis of programs containing floating-point operators has become a priority. However, correctly defining the semantics of common implementations of floating-point is tricky, because semantics may change according to many factors beyond source-code level, such as choices made by compilers. We here give concrete examples of problems that can appear and solutions for implementing in analysis software.
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Updated on 2 November 2026.