What is the best way to reduce the noise in Cycles? I have 2 4800 series ATI cards that are too old for gpu rendering and my processor tends to overheat if i got beyond 300 samples. Is there any trick to this? Honestly after the first 20 samples there never seems to be a difference or any clarity.
thanks
Lightening is a key for less noise.
Use big planes with low value.
Glow shaders give more noise.
Use champ.
He means ‘clamp’. (in render settings. Try 1.3 as a start. Values <1 gives darker image)
But you can use it as a champ. 
Where is this “clamp” variable? Everyone says its Render settings under seed, but its definitely not there. I have the newest version of Blender. Under Integrator i only see Samples (Render, Preview, Seed) Bounces (Max, min) Transparency (Max, Min) and Light Paths (Diffuse, Glossy, Transmission). Then 2 check boxes for Shadows and No Caustics.
I’ve had it for a long time though I used builds of Graphicall.org or buildbot from day 1 with Blender… 
Ah ok. Ill download and give it whirl for kicks and giggles to see if it improves it.
Also turn off Caustics, unless you really need them. And if you do, you will need lots of samples anyway…
Anyways i advice you to upgrade your PC