# Raspberry Pi 5 vs Pi 4 for Neural Amp Modeler: Does the CPU Upgrade Actually Matter?
If you landed here from a search, you probably already know the basics: you can run a neural amp modeler on a Raspberry Pi, shove a guitar into a USB audio interface, and get tones that sound surprisingly close to a real amp. We covered the full build walkthrough over at the original HomeNode post if you need to catch up. This article assumes you’re already there and asking the next logical question: *I have a Pi 4, should I buy a Pi 5, or is that money better spent on strings and beer?*
Short answer: it depends on which software you’re running and how hard you push the buffer. Long answer is below.
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A Bit of Background
The Pi 4 runs a BCM2711, a quad-core Cortex-A72 clocked at 1.8 GHz (boosted from the original 1.5 GHz via firmware). It’s been the workhorse of DIY pedalboard builds since 2019 and it’s genuinely capable — until you ask it to run a full NAM .nam model at a 64-sample buffer and also play a down-tuned E chord that lasts four bars.
The Pi 5 swaps in the BCM2712, a quad-core Cortex-A76 at 2.4 GHz. On paper that’s a big step: A76 cores have roughly 2–2.5× the IPC of A72 cores, and the clock bump adds another 33%. Real-world improvements in compute-heavy tasks tend to land somewhere between those numbers. The question for us is whether that extra headroom translates to reliable sub-10ms latency for live guitar use.
All tests below were done with:
- NAM 0.7.x plugin (standalone
nambinary, ALSA/JACK backend) - The same
.nammodel: a publicly available Fender Deluxe capture at standard resolution (not lite) - Focusrite Scarlett Solo (3rd gen) as the audio interface on all boards
- Raspberry Pi OS Lite 64-bit (Bookworm), fully updated as of early May 2026
- Ambient temperature ~21°C
- Guitar signal: a Telecaster, humbucker in bridge position, playing everything from clean arpeggios to sustained palm-mute chugging
The 4GB and 8GB variants of each board were tested. Spoiler: RAM quantity is essentially irrelevant for NAM specifically — the models are small and the process doesn’t come close to memory bandwidth limits. But we tested both anyway because people ask.
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Dropouts at 64-Sample Buffer
This is the number that matters most for feel. At 48 kHz, a 64-sample buffer gives you roughly 1.33ms of buffer latency, and with driver/system overhead you’re typically looking at 5–8ms round-trip on a clean Pi build. That’s playable. Most guitarists stop noticing latency below about 10ms.
Pi 4 (BCM2711), 64-sample buffer:
Running NAM’s standard-resolution model, the Pi 4 4GB hits dropouts within about 45 seconds of sustained heavy rhythm playing — palm mutes, fast alternate picking, anything that doesn’t let the CPU breathe. CPU usage sits around 78–85% on a single core (NAM’s real-time thread is largely single-threaded in the current architecture), and the JACK buffer underruns start stacking up on the console. The 8GB Pi 4 behaves identically — again, RAM isn’t the constraint here.
Switching to a NAM *lite* model drops that core usage to roughly 55–60%, and dropouts become rare. Totally usable for lighter playing. But if you’re running a full standard model because you care about accuracy, the Pi 4 at 64 samples is unreliable under load.
Pi 5 (BCM2712), 64-sample buffer:
Different story. The same standard-resolution NAM model on the Pi 5 runs the real-time core at 45–52% usage during the same heavy rhythm sections. Dropouts at 64 samples: essentially zero across 30-minute test sessions. We ran the “worst case” deliberately — full distorted chug, open low E ringing out — and it held. The A76 architecture handles the floating-point workload the LSTM-based inference leans on more efficiently than the A72.
Verdict on dropouts: If you care about running full-quality .nam models at 64-sample buffer, the Pi 5 is the only board in this lineup that does it without crossing your fingers.
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Sustained CPU Load at 128-Sample Buffer
At 128 samples / 48 kHz, you’re around 2.67ms buffer latency, realistically 8–12ms round-trip. Borderline, but acceptable for practice or recording.
Pi 4 at 128-sample: CPU core usage drops to around 60–68% for the same NAM standard model. Dropouts are rare but not absent — maybe one every 10–15 minutes of playing. Usable. If this is your practice rig and you’re not gigging with it, you can live here.
Pi 5 at 128-sample: Core usage sits around 32–38%. It’s almost boring to report. The system is not working hard.
One thing worth noting: at 128 samples on both boards, you can actually add GuitarML Proteus or Aida-X captures *in addition* to the NAM model with minimal penalty on the Pi 5, which opens up running two captures in series (amp + cab sim from different sources, for example). On the Pi 4, adding a second model at 128 samples pushes you back into dropout territory.
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Thermal Throttling: The Real-World Problem Nobody Warns You About
The Pi 5 is faster, but it also runs hotter. This matters for guitarists more than it might seem, because a pedalboard or gig bag is not a server rack.
Pi 4 without active cooling: Hits around 70–75°C under sustained NAM load. Throttles at 80°C. In a closed enclosure (like a Pelican case or a 3D-printed pedalboard housing), we’ve seen it touch 82°C after about 25 minutes, which means the CPU drops to ~1.5 GHz and your dropout rate spikes. With a passive heatsink and ventilation holes, it holds below 75°C fine.
Pi 5 without active cooling: Reaches 82–85°C during sustained load in free air. Thermal throttle kicks in at 85°C on the Pi 5 by default. In a closed box, this happens *fast* — sometimes inside 10 minutes. At that point, performance drops enough that you start losing the advantage you paid for. The Pi 5 without active cooling in a sealed enclosure is actually *worse* in practice than a Pi 4 in the same enclosure, because it throttles more aggressively.
Pi 5 with the official active cooler: Holds at 48–55°C under sustained load. No throttling. This is the configuration that delivers the dropout-free numbers mentioned above. If you’re buying a Pi 5 for audio, budget for the active cooler or an equivalent third-party fan solution. It’s not optional.
The active cooler adds a few mm of height to your build, which is annoying for tight enclosures, but it’s the only reliable path to getting the performance you paid for.
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64-Bit OS: Just Do It
Both boards were tested on 64-bit Raspberry Pi OS. If you’re on 32-bit for any reason, switch. NAM’s inference code uses NEON SIMD intrinsics that have better compiler optimization paths on AArch64. On the Pi 4, switching from 32-bit to 64-bit OS reduced NAM core usage by about 8–10 percentage points in our testing. On the Pi 5 the gap is similar. There’s no good reason to run 32-bit for this use case in 2026.
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USB Bandwidth and the PCIe Question
The Pi 5 has a PCIe Gen 2 interface (Gen 3 capable with a hat, but the onboard connector is Gen 2 — worth clarifying since “PCIe Gen 3” gets thrown around in Pi 5 marketing). For USB audio, this is mostly irrelevant because the Focusrite Scarlett Solo is USB 2.0 and doesn’t come close to USB 3.0 bandwidth limits anyway.
What *does* matter: the Pi 5’s USB controller is separate from the CPU bus in a way that slightly reduces interrupt latency variance compared to the Pi 4. In practice, we saw the Pi 5’s JACK xrun (buffer underrun) count was lower even at identical CPU loads, suggesting the USB audio receive pipeline is a bit more consistent. It’s a small difference but it’s real.
If you’re running a higher-end interface — say, a Focusrite Scarlett 2i2 or a Behringer UCA222 in a chain with other USB devices — the Pi 5’s USB handling is measurably more stable. The UCA222, for context, is USB 1.1 audio class compliant and works fine on both boards, but it caps you at 48 kHz/16-bit, which is fine for guitar but worth knowing.
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Power Draw and Gig-Bag Battery Life
This is where the Pi 5 gives back some of the goodwill it earned on CPU performance.
Pi 4 power draw under NAM load: ~3.8–4.5W at the board. With a Focusrite Scarlett Solo (which draws bus power), total system draw is roughly 6–7W.
Pi 5 power draw under NAM load (with active cooler fan running): ~6.5–8.5W at the board. Same interface, total system draw roughly 9–11W.
An Anker 737 (25,600 mAh, 140W) has about 92Wh of usable capacity. At 7W total draw, a Pi 4 rig gets you roughly 13 hours. At 10W average, a Pi 5 rig gets roughly 9 hours. Both are fine for a gig or a day of practice. But if you’re running a smaller battery — a 10,000 mAh 5V pack, for instance — you’re looking at maybe 3.5 hours vs 2.5 hours, which starts to feel meaningful.
For the Anker 737 use case specifically: both boards are comfortably powered through a USB-C PD cable. The Pi 5 requires a 5A/25W capable supply to avoid the low-voltage warning, and the Anker 737 handles that fine. Cheaper batteries that can only deliver 3A may cause the Pi 5 to throttle, which defeats the purpose.
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Comparison Summary
| Metric | Pi 4 (BCM2711) | Pi 5 (BCM2712) | |—|—|—| | NAM standard model, 64-sample, dropouts | Frequent under load | Essentially none | | NAM standard model, 128-sample, dropouts | Rare | Essentially none | | Core CPU % (NAM std, 64-sample) | 78–85% | 45–52% | | Thermal throttle risk (closed enclosure) | Moderate | High without active cooling | | Thermal throttle with active cooling | N/A needed | None | | Total system power draw | ~6–7W | ~9–11W | | 64-bit OS benefit | Yes (~8–10% gain) | Yes (~8–10% gain) | | USB audio stability | Good | Slightly better | | RAM difference (4GB vs 8GB) | Irrelevant for NAM | Irrelevant for NAM | | Current retail (board only) | ~$55–65 CAD | ~$90–100 CAD |
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Conclusion: Who Should Upgrade?
Keep the Pi 4 if: You’re running NAM lite models, or you’re happy at 128-sample buffer for practice use, or your use case is recording into a DAW where you can tolerate slightly higher latency. The Pi 4 is genuinely capable here and costs meaningfully less. Pair it with a NAM lite model and a 128-sample buffer, and you have a rig that works without drama.
Buy the Pi 5 if: You want to run full standard-resolution .nam captures at 64-sample buffer reliably, especially under hard playing. If you’re doing live performance, heavier rhythm work, or you want the headroom to run Aida-X or GuitarML Proteus alongside NAM without fighting dropouts, the Pi 5 is the right call. Budget for the active cooler — it’s not optional, it’s part of the bill of materials.
In both cases: Run 64-bit Raspberry Pi OS Bookworm, use a quality USB interface (the Focusrite Scarlett Solo is a solid choice for this build), and don’t try to run a Pi 5 in a sealed box without airflow and then blame the hardware when it throttles.
The Pi 5 is a real improvement for this specific workload. The A76 cores handle the LSTM inference in NAM noticeably better than the A72. Whether that’s worth ~$35–40 CAD extra and higher power consumption is a question only your use case can answer.
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