Cost & deployment
The Cluster You Already Own
TCO On-prem vs cloud R&D economics
The best cluster for most quantum chemistry in 2026 is the workstation already under your desk. Not because clusters are bad — because the jobs got smaller and the desktop got faster. A 16-core box now converges a fullerene at B3LYP in about three and a half minutes and a cholesterol-sized local-correlation (DLPNO-MP2) job in four. Once the compute you need fits on hardware you own, the whole cost conversation flips from “how many core-hours do we buy” to “why are we renting at all.”
Let's put real numbers on it — both the throughput and the total cost of ownership.
What a 16-core desktop already does
These are measured Hilbeon wall-clock times on a single 16-core node, each written up in its own post so you can check the setup:
| Job | Size | Wall time, one desktop | Write-up |
|---|---|---|---|
| C₆₀ fullerene, B3LYP/3-21G | 60 atoms | 215 s | C60 in 215 seconds |
| Cholesterol DLPNO-MP2 (74 atoms) | local-correlation energy | 247 s · 99.7% recovered | DLPNO on the desktop |
| Orforglipron, RHF | 113 atoms · 1006 basis functions | converged, bit-identical ×2 machines | Inside orforglipron |
A fullerene, a cholesterol-sized local-correlation job, and a 113-atom oral drug — none of them needed a queue, an allocation request, or a data-transfer plan. They needed a desktop and a few minutes.
The rental meter
Now price the same 16 cores in the cloud. A fair match to a 16-core desktop is an AWS c7i.8xlarge — 32 vCPUs (16 physical cores with hyper-threading) and 64 GiB of memory — at roughly $1.428 per hour on-demand. So a single C60 run costs about $0.085 of compute. Cheap! That is exactly the number a cloud calculator shows you, and exactly why the per-job framing is a trap.
You don't run one job. You run a research program. Keep one 16-core node genuinely busy just four hours a working day — a conservative load for anyone doing method development or a screening campaign — and the meter reads:
| Line item | Own the workstation | Rent the equivalent (cloud) |
|---|---|---|
| Hardware | ~$2,500 once | $0 capex |
| Compute, 1 year @ 4 h/day (880 h) | ~$100 electricity | $1,257 (880 × $1.428) |
| Compute, 3 years | ~$300 electricity | $3,770 |
| Pulling results back (egress) | $0 — already local | $0.09 / GB, one way |
| Queue wait | none — interactive | hours, shared allocation |
| 3-year total | ~$2,800 | ~$3,770+ |
At a modest four hours a day the workstation breaks even in its third year and comes out roughly $1,000 cheaper over three. Double the load to eight hours — normal for an active screening or method-dev user — and the cloud bill is about $2,513 a year: the desktop pays for itself in around thirteen months, then keeps running for the price of electricity.
Assumptions: cloud compute at the c7i.8xlarge on-demand rate; electricity ~$100/year (≈250 W under load, 4 h/day, ~$0.15/kWh — rate-dependent). The throughput jobs above are single-point energies (see the linked posts for geometry and level-of-theory details); they measure wall-clock, not full optimizations.
The costs that never make the calculator
The table above is generous to the cloud, because it only counts core-hours. Three real taxes sit outside it:
- Egress is a one-way street. Wavefunction dumps, orbital and density cubes, NCI grids, MD trajectories — a live orbital cube is ~2 MB, an NCI grid ~16 MB, a screening campaign tens of gigabytes. At $0.09/GB every result you want to actually look at is metered on the way out. On the box under your desk it is already on your disk.
- Queue latency dwarfs run time. A 215-second job that waits three hours for a shared allocation has a 98% idle wall-clock. Per-second billing doesn't fix that — only zero-queue, interactive hardware does. Iteration speed, not core price, is what actually gates a project.
- Someone runs the cloud. Machine images, storage lifecycle, spot-interruption handling, IAM — that is salaried DevOps time the core-hour price silently omits. A workstation you turn on.
What this means for whoever signs the invoices: for the steady diet of small-to-mid molecules that most medicinal-chemistry QM actually is, a local workstation plus a tool that uses it well is cheaper and faster to iterate than renting — and the data never leaves your building, which your IP and compliance teams will also appreciate.
Where the cloud still wins — honestly
This is not an anti-cloud argument. The cloud is the right tool for two cases, and we'll say so plainly: rare massive bursts — thousands of cores for a single afternoon, where owning that capacity would be absurd — and genuine zero-capex situations where a one-time hardware spend is the blocker. If your workload is spiky and enormous, rent it. If it's a steady stream of drug-sized molecules, the economics point the other way, and they point hard.
Hilbeon is built for that second world: a package simple enough that the desktop under your desk becomes the whole facility. The throughput above is real, measured, and reproducible — and it runs on-premises, on hardware you already have, with your data staying exactly where it is.
Turn the box under your desk into the facility
Start a 30-day guided pilot — every method, every core, your GPU — and see what your own workstation does with your compounds.
References & sources
- AWS EC2 on-demand pricing (c7i.8xlarge, 32 vCPU / 64 GiB, ~$1.428/hr; corroborated via instances.vantage.sh) — aws.amazon.com/ec2/pricing/on-demand
- AWS data-transfer (egress) pricing, $0.09/GB first 10 TB — aws.amazon.com/ec2/pricing/data-transfer
- C60 B3LYP timing — A Fullerene Before Coffee
- Orforglipron scale — Inside Orforglipron