I try to blur hdri bat i obtain the same bad image whit a lot of noise....maybe i wrong something!
There's anyone can post an blur hdri whit sun for shadows?
Thanks and sorry if i don't understand what you say
hdri vs whitout
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Please add your OS and Hardware Configuration in your signature, it makes it easier for us to help you analyze problems. Example: Win 7 64 | Geforce GTX680 | i7 3770 | 16GB
Please add your OS and Hardware Configuration in your signature, it makes it easier for us to help you analyze problems. Example: Win 7 64 | Geforce GTX680 | i7 3770 | 16GB
Well, so far, as I have a weak GPU with only 512 MB of Ram, I have used low res LDR jpeg image created in photoshop using gradient or/and an orange spot to fake the sun, and I found no real difference with huge definition HDR images that I have tested... 

French Blender user - CPU : intel Quad QX9650 at 3GHz - 8GB of RAM - Windows 7 Pro 64 bits. Display GPU : GeForce GTX 480 (2 Samsung 2443BW-1920x1600 monitors). External GPUs : two EVGA GTX 580 3GB in a Cubix GPU-Xpander Pro 2. NVidia Driver : 368.22.