Civ5 starts to stutter at some point

At some point during the game the pointer moves slowly and graphics scrolling becomes tedious because of the image stuttering. After a while the game resumes its normal pace, then restarts the stutter, then normal again and so on as a tide. Each phase is a ten minutes long approx.

Each normal and slow running phase of the game corresponds respectively to a raise and a stop of the fan noise of the graphics adapter.

I have lowered all Civ5 graphic options unsuccessfully

Operating System: Windows XP Professional Service Pack 3
Processor: AMD Athlon(tm) 64 X2 Dual Core Processor 6000+, MMX, 3DNow (2 CPUs), ~3.0GHz
Memory: 4 GB RAM
DirectX Version: DirectX 9.0c
Card name: ATI Radeon HD 4600 Series
Display Memory: 512.0 MB
Current Mode: 1680 x 1050 (32 bit) (60Hz)

Nobody here answered to the post above.
Now I've some news about it.

When Civ5 starts stuttering, I've captured my PC status in the attached pic

You notice the 100% CPU strangeness usage, and more strange is the high CPU usage by "zone alarm client" (no ZA popup appears - for who knows ZA)
When after 3-4 minutes zclient CPU usage returns to 0, then Civ5 runs normally again

I've tested both with steam online and offline, but the result is the same

Any clues?

Just as note, because I never used before the SpeedFan tools, are the temps inside their standard values?

I've seen an increased processor load on my system, when some programs can't connect.
When Skype loses the connection, it will open nearly 1000s of new channels to get a response, which gives my firewall an incredible work load and the processor jumps to 100% system load.
I guess something like this could apply too, depending on system configuration, etc.
So for testing i'd suggest:
- Shut down nearly every internet connected program (besides the firewall, sure)
- Unplug your connection. Many programs will recognize when the connection is missing and will not do anything.


Temperatures are fine. You should keep an eye on them when they pass 80, then it could get critical for the processor (not sure, i guess tokala knows about that better), but graphics card can even bear more than 100°C.

The temps are okay, but Zonealarm is, to speak frankly, a useless POS. Same is valid for all those "personal firewalls" in general. Uninstall it, problem solved

Try lowering your resolution. 1680x1050 is a high res, and demands more from the card. Lower resolutions will help reduce your cards workload, and you could maybe raise some in game options.

Finally I got rid of it.
It was a CPU thermal throttling issue. See the discussion below.

http://forums.civfanatics.com/showthread.php?t=395086

I strongly suggest to everyone having freezes, crashes, stutters, etc... to download Core Temp (freeware), install it and check CPU temps while playing Civ5 in windowed mode.
It may save you lots of time

Looks like speedfan does not spit out the correct values
A shame, as it is very useful for costumized fan speed profiles, and it does correctly read out my GPU temperature.

Counterchecked with coretemp, and it shows 5° less than speedfan with my C2D.