When I first got my comp running a couple of months ago, I had no extra fans installed at all.
Just my motherboard, videocard, processor/heatsink/fan, harddrive, and that's it.
I ran speedfan and found that my temperature was at 51 or 52 C or so while doing minor tasks. This of course showed the fire symbol next to my temperature, making me think that my CPU was overheating for a while.
After finding that everything was running fine, I decided to not really care anymore and stopped checking my temps.
I began gaming again sometime between then and now with at first no problems. My old video card (Radeon 8500) then went to [content edited] (fan was dying, and would stop completely until it got rest), This of course made my comp freeze everytime it ran out of juice. I let this happen a few times before going to get a new video card (Radeon 9600 XT). When I installed the card and began to play games, I was spammed via audio through my headphones with the message "System Failed CPU Test." My motherboard is an Asus A7N8X-E Deluxe, which is why I receive the audio warnings. The message would repeat repeatedly throughout my time spent in the game. As soon as I stopped, the message stopped.
This prompted me to install Asus Probe to check my temperatures again. Of course, my temperatures were much higher now than before. 60 C or so.
I bought an 80MM fan, which I placed on my side panel before learning the proper airflow diagram, so that didn't seem to help much. I readjusted my heatsink and the messages stopped for a while, then began again after a few days. I then purchased a 120 MM fan for the front of my computer, and relocated my 80MM to the back as an exhaust fan. My temperatures are much better now, being at 49 to 51 C at idle, and 55-56 C at gaming. I no longer receive the annoying messages.
So a few questions I have...
What are the actual ideal/decent temperatures for a Sempron 2800+ ? I've read many different opinions, some which state anything below 60 is fine, some stating that anything above 52 is too high.
Could my new video card be responsible for higher CPU heat? This would make sense to me since I didn't need fans before the new video card, and now I do need them.
Is the stock heatsink for Sempron 2800 decent? Or should I upgrade?
How important is thermal paste? There was already a rectangle grey claylike substance on the stock heatsink. Would that have sufficed?
If I have 3 fans, should my setup be 120MM front intake, two 80/100 MM exhaust for side and back? (This is what my tower allows for).
Any other opinions would be nice. I also cannot spend much money to fix my problem so hopefully someone has a poor man's solution for this.
There is no real 'ideal' temperature for any CPU, as it will vary from system to system. Generally speaking, keeping the temperature under 60C at load is a good rule to follow. Though, the max die temp being 90C on the Socket A Semprons, some systems will start becomming unstable around 60 or 65C, as you probably were experiencing.
The 9600XT does generate more heat than that of the 8500, and the AGP slot being somewhat close to the CPU, dont' be suprised if the temp rises 1-3 degrees.
As for cooling, the stock heatsink should suffice, as it is meant to 'get the job done'. I don't see a real need for an upgraded heatsink, even in your situation. It is summertime in the Northern Hemisphere, so expect temperatures to be higher.
The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.