I cannot comment on much of your request as I have not found a motherboard w/o sound that I like yet for an 800Mhz PIII.
But the difference between the OEM and Retail CPU is this; The OEM unit typically comes without a fan (i.e. bare processor) and requires you to provide a fan. This is the best way to go. I would recommend the Antec cooling fan (
www.antec-inc.com). It is a dual ball-bearing fan unit. They actually have 2 different units, one has a very large heavy duty heat sink (The monster) and will probably out last your computer.
The retail processor, is the Intel box set with cooling fan.
I really have not had any problems with the Intel provided fan, but the Antec fan on my 600E keeps the processor about 5 degrees cooler than the Intel fan. Keep in mind, because it is a dual fan unit, it does draw more power. Not a problem for me as I have a 300W power supply from Antec.
I would look for the Antec fan at other places, as they charge full retail for it on thier WEB site ($39.95 U.S.).
Hope this helps.
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Roy "Skuzzy" Neese
President, AppLink Corp.
http://www.applink.netskuzzy@applink.net