Renders left overnight run slow?

[Bosseye]

Quick question - I often leave renders running overnight so that they're done when I arrive at work the next morning. However, twice now, apparently at random I've had renders that have barely progressed since I left them the night before.

Normal performance when I arrive in the morning is to see a smooth render sitting at around 5000spp running at around 18k s/s with a total render time of around 16hrs (GPU rendering is off)

However last night I left one running at around half an hour rendering time when it had reached 190spp at 55k. I arrived in this morning and after 16hrs rendering its still only on 202spp at a measly 5k. Naturally it still looks hideously grainy.

I've just set the render going again from scratch and after and hour its already on 220spp at 55k so running essentially how I left it last night.

So something has gone wrong overnight but what? This is the second time I've had this, but as I say everything else I left overnight has processed fine.

Any thoughts? All I do is set background mode to 'off' and then turn off my monitors. I'm running Indigo v3.0.10

[Borgleader]

This is going to sound really dumb, but is it possible some sort of power saving feature kicked in which kept Indigo from using your computer's full computing power after you closed the monitor and went to sleep?

[Headroom]

That is not dumb at all!

On my iMac if I forget to set it not to go to sleep in the energy saver preference screen that's exactly what happens.
Ut does not matter if I leave the machine with all cores blasting away at full load. It will simply go to sleep if I forget that setting.

[Bosseye]

This is going to sound really dumb, but is it possible some sort of power saving feature kicked in which kept Indigo from using your computer's full computing power after you closed the monitor and went to sleep?

Not dumb I don't think so though, theres no power saving features set up to kick in after a set amount of time. Plus the fact that I do the same routine every time and 90% of the time no issues - just these two issues with two different models and only recently too...

I'll double and triple check the power saving settings though...

[Frutiger]

Does anyone else always have a really warm office in the morning after an overnight render, or is it just me? It always smells like the inside of a computer.

But to the point: Is this error happening on the same render on different nights? Is it possible you've changed something in the scene that takes alot longer to resolve?