CoD has artifacts but not BF2 and strange CPU downclocking

I was overclocking my ATI x700 a few days back and I started to notice some artifacts when I was playing CoD and BF2. Because of this I decided to go back to my default settings. I have no problems playing BF2 now but Call of Duty still shows artifacts once and a while.

I also noticed something interesting relating to my CPU clock and temperature. When I was playing BF2 my CPU was set to Max Performance and was running at 2.0Ghz. My temps were around 50C. However after I finished BF2 I noticed something strange on my NHC graphs. The temperature steadily increased until it got to about 76-79C. Then my CPU clock dropped to 1.0GHz which caused my temp to drop to about 60C.

This didn't affect my game (so far as I can tell) but it concerns me that this happened. Has anyone else noticed this before?
Tim

 

So now you have artifacts at default clocks? Did this happen before or after you tried overclocking? If your CPU keeps underclocking itself, you might want to try reinstalling your power management drivers or something... For the 76-79C are you talking about your Video card or CPU? If it is your GPU then that’s not all that bad, but if its your CPU that’s quite hot. Are any vents clogged with dust or anything?

 

Only with Call of Duty. I have no artifacts at the default clocks with BF2 or when I run the ATT test.

I think this only happened after overclocking.

Yeah 76-79C CPU. That is when the system appears to downclock itself to 1.0Ghz. I am sure this has been happening all along but I am not sure what setting is causing it (I use Notebook Hardware control).

I have been looking for a GPU temp reader but haven't found one yet.

Oh and I cleaned my vents today...lets just say I should do that more often. That dropped the normal usage temps by 5C.
Tim

 

Well, if one benchmark fails, and others don't, then it just means that one benchmark does something that the others don't. If you're getting artifacts in *any* game or application, and you didn't get them before you overclocked, then there is a real problem.

In other words, it doesn't really matter whether it only happens in COD. If it happens, it happens.

What if you underclock below stock speeds? Does it go away then?
Did it have any effect when you cleaned the vents?
Have you messed with the GPU's firmware or anything like that when you overclocked?
And of course, have you reinstalled the driver?

 

the CPU downclocks because of overheating, you may try to undervolt it a little bit to reduce heat, then see if that happens again
or maybe you fans and heatsink have some trouble , i believe you can't have artifacts if running a stock speed

 

What you mean is, you *shouldn't* get artifacts when running at stock speed...

Of course it can happen.

 

Thanks for the replies guys. Today was a little crazy since I changed my ISP so that is why I wasn't able to reply.

I am going to re-install Call of Duty and see if that fixes the problem. I just played 4 hours of BF2 and Red Orchestra without any artifacting so I think it was something with the install.
Tim