Specification Update:
The Premiere 3U Server comes with Intel Celeron D 352 single core CPU at 3.2GHz. It’s on Cedarmill (90nm) architecture from Q2 of 2006 with 86W TDP.
Intel® Celeron® D Processor 352 (512K Cache, 3.20 GHz, 533 MHz FSB) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com
I successfully replaced this CPU with the latest revision of Cedarmill (65nm) from Q1 of 2007 which is the Intel Celeron D 365 single core CPU at 3.6GHz with 65W TDP.
Intel® Celeron® D Processor 365 (512K Cache, 3.60 GHz, 533 MHz FSB) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com
The new CPU should be faster while consuming a few less Watts and generating a little less heat. The stock CPU cooler is a Silverstone passive heatsink (copper) which is more than adequate.
I also upgraded the stock 512MB DDR2 533MHz (PC2 4200) RAM with Corsair (2x1GB) DDR2 533 MHz (PC2 4200). While at it, I replaced the CR2032 CMOS battery with a fresh one.