If I use a processor at 100% constantly for several hours, can that damage the machine?
CPU usage at 100% for several hours
cpu usage
Related Solutions
As long as the system is adequately cooled, it won't be a problem. For a laptop, this is a greater concern and you would be well advised to make sure that vents have adequate clearance and that the ambient temperature is kept in check. You'd also want to clean the dust out of the system every so often too. The same routines apply to desktop systems too, but they often have more space for better cooling. Small form factor (SFF) systems and iMacs require care similar to laptops because of their design.
If you can offload rendering to a dedicated system, you might be better off overall, but it's not necessary.
tl;dr– Issues like overheating and excessive wearing can be important considerations for computers that handle heavier loads.
A lot of folks do run their computers continuously at ~100%. This is common practice in computational work, e.g. with engineering simulations or data analysis.
There're two common things to watch out for:
Overheating:
Is your CPU, GPU, motherboard, RAM, disk, etc., getting too hot?Excessive wearing:
Is a piece of hardware that can get worn out being used too much? For example, some consumer disk drives aren't made to be constantly reading/writing data.
1: Overheating issues.
CPU overheating:
In most cases, most heat will come from your CPU – which'll likely be the concern if you're observing 100% CPU usage (which is different from 100% GPU usage, 100% disk usage, 100% network usage, etc.). So, monitoring the CPU temperature is usually the initial focus.Motherboard overheating:
A related issue is the motherboard's temperature. A lot of folks ignore it and assume that it's probably fine as long as the other hardware temperatures are in-control, which seems to be a reasonable guestimate in most cases so long as there's also good air circulation inside of the box. This can be more dubious in the case of compact devices, e.g. laptops.GPU overheating:
GPU temperatures can be a big issue for folks who make heavy use of the GPU, including gamers, graphics professionals, and those who use GPU's as computational co-processors. I think I've seen even little Flash games in a browser go hard on a GPU, presumably due to inefficiency.RAM (memory) overheating:
RAM (memory) temperatures can be an issue especially with highly overclocked RAM. Some vendors'll sell fans with their high-frequency RAM for this reason.Disk overheating:
Some disk drives, e.g. 15,000-RPM hard disks, can have trouble with overheating. I haven't heard of overheating being a big problem with most lower-speed hard-disk drives (HDD's) and solid-state drives (SSD's).
There're other heats that one might watch out for, e.g. a heavily used server might watch out for heating on its network card while a computer with an embedded radio device might watch out there, but those seem to be less common sources of concern for typical users.
2. Excessive wearing issues.
Disk wearing:
Most(I think?) disk drives aren't made to be continuously used at max capacity. So if you have an app that's constantly maxing out a disk drive, e.g. if it's constantly rewriting log files, then that might be something to check into. Servers and professional workstations often have disk drives designed to handle heavier loads.Fan wearing:
Cooling fans continuously running at max might get worn out. A complicating issue with fans can be that if one wears out, but you don't notice it or monitor the related temperatures, then something might get excessively hot before the fan's failure is noticed.
Power-supply unit (PSU) wearing can also be an issue.
Discussion
If your CPU is running at 100% in short bursts, I wouldn't typically be too concerned by that in most cases.
If it's a common thing for your computer, especially over long time periods, you may want to understand the associated heat and wear issues. Professional users, gamers, and other power users often design their own computers specific to their anticipated usage.
Best Answer
If you have adequate cooling, then no. In general, your computer should be able to sustain 100% load for long time. (I've run my laptop for days under 100% load for CPUs and GPU and didn't have any problems).
Also, if your computer is relatively new (say less than 5 years old) it will shut down automatically in case it overheats.
My recommendation is to get some sort of hardware monitoring program like HWMonitor for example and run it while running your task. If the temperatures rise to dangerous levels (I can't tell you what is dangerous for you, since you provided almost no information), you'll be able to see and stop the demanding program.
Also the temperatures will rise quickly, so if they aren't dangerous after 20 or so minutes, then they probably won't reach dangerous levels.
Another thing to watch out for are low voltages. HWMonitor will provide voltage readings. They should be within ±5% of stated voltage for positive voltages and within ±10% for negative voltages. If you do overload your PSU, it should also automatically shutdown, but on cheaper units restarts and Bluse Screens of Death are possible too.