New CPU Cooler Speed/Cooling question

I have just installed a new Dynatron P985 CPU Cooler on my computer. It has the 4 pin pwm connector on it. It fits perfectly and plugs right in to the 4 pin jack on my mob. Although the fan is supposed to idle at 700 RPM, it never goes below 1600 RPM. It idles at between 1600 and 1670 RPM. The processor temps at this speed stay at approx 51 C. My old cooler kept the processor at the same temps but at approx 1100 RPM. My question: Is this anything to be concerned about or is it running normally on my system? I used Antec Formula 5 Silver Thermal Compound.
Thanks for any insight as I am unable to get any support from Dynatron or the supplier.

51 C is a normal dual core operating temp on most systems and really nothi ng to be concerned about, however i do see your point that the new cooler installation is running at a higher RPM just to keep temps the same as the old one did.

I guess this has you thinking 'Why did i bother'?

There are a few variables that could be causing this but i need a bit more info in order to troubleshoot it for you.

Could you give us your Make and Model of CPU and Motherboard and did you apply the compound thinly and evenly?

It sounds to me as if the cooler is working overtime to keep the heat levels down, although it shouldnt be! (hence the higher than expected RPM idle speeds)

My guess would be the issue is caused a wrongly applied application of the Thermal Paste!

This may, or may not settle down with time.....although it seems likely we may have to remove the CPU, clean and re-apply the paste again to see if this helps at all

Regards

Thanks
I believe I got the right amount of compound on the processor (about half size of a grain of rice) and spread it on with a razor blade. I took the compound off that came on the heatsink and applied a small amount of Formula 5. The instructions said to stick your finger in a plastic bag, put a small amount of compound on it, and apply it to the heatsink in a circular motion. Does this sound right? Should I have put compound on both the processor and the heat sink?
My processor is a Intel Pentium 4, 3.4 GHz, socket LGA775
My board is a Intel D915GAG.
I appreciate your feedback.
Ron

No need to put the paste on the heatsink, CPU only!

The instructions given sound OK however if feel that maybe not enough paste has been applied.....this is a very delicate procedure and may take a few tries to get it right.

You should try i slightly thicker application of it i feel......Pull the CPU out and remove the current application and then try applying a slightly thicker coat using the same method as before.

Re-install and let us know if any change?

Regards

You might want to use alcohol / surface purifier before you reapply the thermal compound. I belief your temp is around 50+ because your heatsink fan have low rpm = low heat transfer, most lightly for silent purposes.

Hi
I used alcohol before. I will report back to you after I have reapplied the compound.
Thanks
Ron

I cleaned the surfaces with alcohol and wiped with a lint free cloth then reapplied compound to processor only. The results are exactly the same. The heatsink has a round copper contact which does not completely cover the square processor. I wonder if I should have applied the compound to the heatsink instead? Please let me know what you think.
Thanks
Ron

You dont need to apply it on the heatsink. I personally think that the problem lies on your low fan rpm.

Thanks
I guess I will replace the cooler.
Ron