Strange behavior

[Karlo Bala]

Sometimes when I load engine into Arena, engine work at 1/2 or even at 1/4 of expected speed. When look in task manager I can see that engine use more than 90% processor time. I have 1GB ram and I didn't find any memory swapping from HD to ram. This is happening with almost every engine I have. What could be the reason for such behavior(cache pollution, memory fragmentation, hardware bug)?

[Dirt]

Sometimes when I load engine into Arena, engine work at 1/2 or even at 1/4 of expected speed. When look in task manager I can see that engine use more than 90% processor time. I have 1GB ram and I didn't find any memory swapping from HD to ram. This is happening with almost every engine I have. What could be the reason for such behavior(cache pollution, memory fragmentation, hardware bug)? :?

Some processors will slow down if they get too hot, and for all I know for other reasons too. Did your computer come with a utility you can run that can check that it is running at full speed?

[Karlo Bala]

Sometimes when I load engine into Arena, engine work at 1/2 or even at 1/4 of expected speed. When look in task manager I can see that engine use more than 90% processor time. I have 1GB ram and I didn't find any memory swapping from HD to ram. This is happening with almost every engine I have. What could be the reason for such behavior(cache pollution, memory fragmentation, hardware bug)?

Some processors will slow down if they get too hot, and for all I know for other reasons too. Did your computer come with a utility you can run that can check that it is running at full speed?

I doubt that my old northwood celeron has such capabilities. Sometimes reloading engine fix the problem, but sometimes not

[Dann Corbit]

Sometimes when I load engine into Arena, engine work at 1/2 or even at 1/4 of expected speed. When look in task manager I can see that engine use more than 90% processor time. I have 1GB ram and I didn't find any memory swapping from HD to ram. This is happening with almost every engine I have. What could be the reason for such behavior(cache pollution, memory fragmentation, hardware bug)?

What indicator are you using for your estimate of 1/2 or 1/4 speed?

Sometimes, when an engine has a well filled hash table, the earlier plies will give really low NPS figures, but you will see that it finishes the plies very quickly. And so really, rather than underperforming the engine is overperforming. So there can be serious deception if you are using NPS as a figure of compute power.

[Karlo Bala]

Sometimes when I load engine into Arena, engine work at 1/2 or even at 1/4 of expected speed. When look in task manager I can see that engine use more than 90% processor time. I have 1GB ram and I didn't find any memory swapping from HD to ram. This is happening with almost every engine I have. What could be the reason for such behavior(cache pollution, memory fragmentation, hardware bug)?

What indicator are you using for your estimate of 1/2 or 1/4 speed?

Sometimes, when an engine has a well filled hash table, the earlier plies will give really low NPS figures, but you will see that it finishes the plies very quickly. And so really, rather than underperforming the engine is overperforming. So there can be serious deception if you are using NPS as a figure of compute power.

As an indicator I'm using NPS. I have celeron 2.6gh with 1GB RAM. On my comp normal NPS is(was for years): old Crafty 600-700 KN/s Fruit 300-400 KN/s, Romi about 1.000 KN/s, Hamsters 500-600 KN/s, etc.

Sometimes when I start engine match NPS drop to 1/4 and stay low during and after match. Problem is that in that case I don't see any unusual activities (for example HD). Sometimes it help if I reload engines. Of course I'm not talking about nps at low depth, but about stabilized nps. I'm using Arena1.99beta3.

[Alessandro Scotti]

You can try to open the Task Manager, go to the Process view and sort the processes by CPU time, this will show you if there is some process "stealing" CPU time from the chess engine (at times, this could even be another chess engine that failed to unload properly or is pondering).

[adams161]

Hi,

Have you hecked that the cpu is not sleeping? Maybe its going into some sort of energy/power saving mode?

Mike