Most missed deadlines are missed silently, hours in advance, by people who never did the one calculation that would have warned them. You can know at
Most missed deadlines are missed silently, hours in advance, by people who never did the one calculation that would have warned them. You can know at 6pm whether a render will be done by 9am, and if it will not, you still have time to do something about it. The maths is quick, and it has saved me from more than one midnight panic.
To know if your render will finish in time, work out hours needed = (frames remaining x time per frame) divided by how many machines you can run at once, then compare it to the hours you actually have. Use a realistic per-frame time from a heavy frame, not an easy one, add 15 to 20 percent for overhead and the odd failed frame, and remember that multiple GPUs do not scale perfectly, so eight cards finish nearer six and a half times faster, not eight. If the number is larger than your available hours, you need more machines or a leaner scene, and you need to act now, not at midnight.
The calculation, worked through
Say you have 600 frames left, each taking about 3 minutes on a heavy frame, which is 1800 minutes or 30 hours on a single card. You have 10 hours until delivery. Thirty hours of work in a ten-hour window means you need to be roughly three times faster, so a single machine will not make it. Four GPUs running together get you near 3.6 times faster, bringing it to a bit over 8 hours, which fits inside 10 with a buffer. That is the entire decision, and you can make it at 6pm instead of discovering the problem at 3am.
| Hours needed vs available | Will it finish? | What to do |
|---|---|---|
| Needed well under available | Yes, comfortably | Render as planned, keep a small buffer |
| Needed close to available | Risky | Optimize a little, or add one machine for safety |
| Needed above available | No, not on one machine | Spread across more GPUs, or cut scene cost, now |
When the maths says no
If the number comes back larger than your window, you have two real levers, and both work better the earlier you pull them. Cutting per-frame cost through optimization buys some time. Adding machines buys more. When I run the numbers and one card clearly will not make it, I spread the sequence across rented GPUs for that job, with the caveat that the meter runs from power-on, setup included, so it suits a planned deadline push rather than leaving a machine on all day. The full routine for staying out of this corner in the first place is in the delivery playbook.
If you burst to make a deadline: a weekend render earns 20% back through iRender’s Credit Back, and new accounts get a one-time 100% first-deposit bonus. (Rates change; verify.)
When the maths says one machine will not finish, spreading the sequence across rented GPUs is how I claw the deadline back. iRender describes running your own setup on those machines as “your renders, your rules”. See iRender multi-GPU servers
FAQ
How do I calculate if my render will finish in time?
Multiply the frames remaining by a realistic per-frame time taken from a heavy frame, then divide by how many machines you can run at once to get the hours needed. Add 15 to 20 percent for overhead and failed frames, and use real multi-GPU scaling rather than a clean multiple. Compare that to the hours you have. If needed exceeds available, act now.
My render will not finish in time. What can I do?
You have two levers and both work best early. Optimize the scene to cut per-frame cost, which buys some hours, and add machines by spreading the sequence across rented GPUs, which buys more. Done at 6pm these can save the delivery. Done at 3am, your options shrink fast, which is why doing the calculation early matters.
See more: Driver Crashes During GPU Render: How I Stopped Losing Hours
Image source: MAXON
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