If you take the time to read about CCSI history, you will see that the original rack mounted PC was in the 4U form factor. This was principally a result of the adaptation of the then “state of the art” IBM PC AT desk top computer, to a rack mounted configuration. While 4U was the original “standard” for a rack-mounted computer, it has become less popular as a higher level of integration has been offered with successive generations of motherboards, thus requiring fewer expansion slots and with increasing capacity of hard drives currently as much as 2 Terabytes. 4RU, which is 7.0 inches of vertical rack space, allows sufficient room for 7 full sized expansion cards or even up to a 20 slot passive backplane and as many as 24 Hot Swappable 3.5 inch hard drives. CCSI 4U Performance Servers are the right choice for customers who need more expansion slots than a 2U system supports and more hard drive capacity than a 3U system supports. CCSI 4U Performance Servers are available as single processor, Socket AM 3 AMD Opteron™ servers or AMD Phenom™ servers, Intel Socket 775 Intel Core™ 2 Duo servers, Core™ 2 Quad servers, Socket 1156 or Socket 1366 Core™ i7 servers, dual processor or quad processor, dual core, quad core or six core Socket 1207 AMD Opteron™ servers and Socket 1366 Dual Processor Quad Core Intel Xeon™ servers.
High efficiency power supplies with 80% or higher efficiency rating coupled with low wattage CPUs yield high performance servers that meet green computing platforms standards.