Member Avatar for Adagio

Hello,

I am carrying out computationalsi intensive calculations. Is it possible to have 100% of the processor power dedicated to this task. Normally, system idle process will take 15% - 20% of processor power which normally means the computation takes 1 hour longer.

It is very easy to set the task to high priority on Windows Task Manager but immediately Sysytem Idle Process kicks in after setting the compuational process to high.

If anybody could help this would be much appreciated.

Daniel Gandolfo

  • 3 Contributors
  • 5 Replies
  • 193 Views
  • 5 Days Discussion Span
  • Latest Post Latest Post by alc6379

Dani AI

Generated

Short summary: the Windows "System Idle Process" is just a counter for unused CPU cycles, not a competing program. If a heavy compute job never reaches full CPU use after raising its priority (as reported by ), the cause is almost always that the job is not able to consume more cycles — not that Windows is stealing them. and were correct to point toward the application or its environment rather than a registry trick.

Essential checks and quick diagnostics:

  1. Determine whether the app is single‑threaded or multi‑threaded (single threads can only use one logical core).
  2. Measure where the program is spending time: CPU (compute), waiting on disk/network I/O, blocked on locks, or stalled on memory/cache. Use Process Explorer (Threads view), Resource Monitor (resmon), or PerfMon counters to collect per‑thread CPU, disk queue length, page faults, and processor queue length.
  3. Look for high DPC/interrupt or driver activity (these can consume CPU invisibly to the app). Windows Performance Recorder/Analyzer or Process Explorer can help here.
  4. Check system configuration: power plan, background services, antivirus scans, and CPU affinity (dedicating cores to the job can help on a shared box).

Common remedies (ordered by cost/impact):

  • If the program is single‑threaded and source is available: profile hotspots and parallelize (OpenMP, thread pools, or data partitioning), compile optimized/release builds, and use tuned libraries (BLAS/MKL) where appropriate.
  • If I/O or paging is the bottleneck: increase RAM, move working data to faster storage, or reduce unnecessary disk access.
  • If the program cannot be changed: run it on a quieter/dedicated machine, set affinity to reserve cores, and minimize background services. Avoid realtime priority — it can make the system unresponsive by starving essential kernel work.

Conclusion: raising priority only affects scheduling order; it does not make non‑CPU work vanish. The next step is systematic profiling (per‑thread CPU, I/O, and DPC/ISR) to find the real bottleneck, or engage the software provider if the application is closed‑source.

Recommended Answers

All 5 Replies

Member Avatar for JoetjeF

You can start the application using the start command:

start /high notepad.exe

There are 5 priorities: /low, /belownormal, /normal, /high and /realtime. It's usually not adviced to use /realtime but you can always try of course.

Edit: Probably haven't read your message properly ;) The system idle process uses all processor power that's not used by windows or its applications. If the application only uses 80% of the CPU power it usually means that the CPU is not limiting the application but something else. It could be the way the application is coded. You cannot do much about it anyway, at least not that I'm aware of.

Member Avatar for Adagio

THanks for your reply.

I have tried resetting the priority. I t workds for a few seconds but soon system idle will take ~20% of CPU time.

THe problem must be in the registry or program itself.

Any ideas.

Daniel

Member Avatar for Adagio

--------------------------------------------------------------------------------

Thanks for your reply.

I have tried resetting the priority. It works for a few seconds but soon system idle will take ~20% of CPU time.

The problem must be in the registry or program itself.

Any ideas.

Daniel

Member Avatar for JoetjeF

The only thing you can do is to contact the company who wrote the software. I don't give yoy much change though. As said before, there is nothing you can do. If the application doesn't use 100% then it doesn't need the processor power ;)

An explanation can be that the application needs lots of memory access. As memory access is relatively slow, the processor has to wait till the memory access has finished.

Member Avatar for alc6379

I think JoetjeF is right-- you'll need to talk to the provider of the application. You wouldn't notice the difference between 80% utilisation and 99% utilisation, but you don't want your system to be unresponsive while your app runs. From the sounds of it, whoever programmed the application didn't perform correct optimization of their code, to effectively use processor time.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.