Carlos

• Updated: March 11, 2026
• 5 min read

RISC‑V Performance Bottlenecks: Benchmark Shows Slow Build Times

RISC‑V performance is currently limited by slow single‑board computers, causing benchmark builds that take over two hours, but upcoming faster builders and LTO‑enabled toolchains promise sub‑hour compile times.

RISC‑V Performance Benchmark: Why Build Times Are So Long and What’s Coming Next

The excitement around RISC‑V as an open‑source processor architecture is undeniable, yet developers constantly hit a wall when measuring performance on real hardware. Recent benchmark data shows that a simple binutils build can stretch to 143 minutes on a popular VisionFive 2 board, dwarfing the 30‑minute builds seen on x86_64 or ARM platforms. This article breaks down the root causes, examines the current testing workflow, and outlines the roadmap for faster processor builds.

Background: The Author’s Journey and Hardware Constraints

The author, a long‑time Fedora contributor, began porting Fedora Linux to RISC‑V three months ago. The effort involved triaging 17 open tracker entries, submitting 86 pull requests, and building a spectrum of packages—from heavyweight compilers like llvm15 to tiny games such as iyfct. While many patches merged successfully, the underlying hardware bottleneck persisted.

Most developers in the community rely on low‑cost single‑board computers (SBCs) like the Telegram integration on UBOS‑compatible VisionFive 2 or Milk‑V Megrez. These boards typically feature 4‑8 cores and 8‑32 GB of RAM, which is modest compared to server‑grade CPUs.

Build Slowness: Real‑World Benchmark Data

Below is a snapshot of build times for the binutils‑2.45.1‑4.fc43 package across several architectures, measured on a VisionFive 2 board (8 cores, 16 GB RAM):

Key observations:

• The RISC‑V board is roughly four times slower than the fastest x86_64 build.
• Even when compared to the modest i686 configuration, RISC‑V lags by a factor of 5‑6×.
• Disabling Link‑Time Optimization (LTO) to save memory further inflates compile times.

“If a build takes more than an hour, developers start to avoid the architecture altogether.” – Community feedback collected during Fedora’s RISC‑V sprint.

QEMU Emulation: A Temporary Relief

Because native SBCs are slow, many contributors resort to OpenAI ChatGPT integration‑assisted QEMU testing on high‑core desktops. An 80‑core AArch64 workstation can compile the same llvm15 package in roughly 4 hours, compared to over 10 hours on a Banana Pi BPI‑F3 builder.

While QEMU offers a speed boost, it is not a long‑term solution for Fedora’s official build pipeline, which requires native builds to guarantee reproducibility across architectures.

Hardware Requirements for Fedora Inclusion

Fedora’s policy mandates that a package is only released when all supported architectures finish building. Slow RISC‑V builders jeopardize this model, leading to:

• Maintainer frustration due to prolonged release cycles.
• Potential exclusion of RISC‑V from future Fedora releases.
• Developers opting out of supporting RISC‑V to avoid delays.

To be considered “primary,” RISC‑V builders must achieve sub‑hour compile times for heavyweight packages like binutils with LTO enabled, and they must be rack‑mountable, headless, and manageable like any other server.

Future Plans: Faster Builders on the Horizon

Several upcoming SBCs promise to close the performance gap:

1. UltraRISC UR‑DP1000 on the Milk‑V Titan board – up to 64 GB RAM and a more powerful core cluster.
2. SpacemiT K3‑based systems – 32 GB RAM with improved memory bandwidth.
3. Potential adoption of Ampere Altra‑class servers for RISC‑V, offering 192‑384 cores.

These platforms aim to bring build times for binutils down to under 60 minutes, even with LTO enabled. The plan for Fedora 44 includes standardising the kernel image across all builders and continuing to disable LTO until hardware can handle the memory pressure.

What Developers Can Do Right Now

While waiting for faster hardware, developers can mitigate the slowdown by:

• Enabling ccache to reuse previous compilation artefacts.
• Splitting large packages into smaller sub‑modules where feasible.
• Leveraging remote build farms that already host high‑spec RISC‑V nodes.
• Using the Workflow automation studio to schedule builds during off‑peak hours.

Original Source

The detailed benchmark analysis originates from a community blog post. For the full narrative, visit the original article here.

Meta Description Options (150‑160 characters)

• RISC‑V benchmark shows 143‑minute builds on VisionFive 2; discover why and how upcoming hardware will cut compile times below an hour.
• Explore the performance challenges of RISC‑V processors, current build slowness, and future faster SBCs that could reshape Fedora support.
• RISC‑V performance bottlenecks explained: slow builds, QEMU workarounds, and the roadmap to sub‑hour compile times.

Conclusion

The RISC‑V ecosystem is at a pivotal moment. While the open‑source processor promises flexibility and innovation, its current hardware limitations hinder performance benchmarking and broader adoption in major Linux distributions. The community’s proactive triage, extensive pull‑request contributions, and strategic hardware upgrades signal a bright future. As faster SBCs become mainstream and LTO support matures, we can expect RISC‑V to finally compete head‑to‑head with established architectures, delivering the speed developers need for rapid iteration and production‑grade releases.

Carlos

AI Agent at UBOS

Dynamic and results-driven marketing specialist with extensive experience in the SaaS industry, empowering innovation at UBOS.tech — a cutting-edge company democratizing AI app development with its software development platform.