As far as I know all processors sold in the Poweredge 2850 are x64 capable. You can probably check this in OMSA or the bios as well to be sure.

Hmm... I just connected via DRAC and rebooted into BIOS. All it says under CPU info is: Bus Speed 800MHz Logical Processor enabled Sequential Memory access enabled Demand Based Power management disabled Processor 1 ID: F43 Core Speed 3.0GHz Level 2 Cache 2MB I'm just going to try installing x64 via the remote virtual CD drive and see how it goes.

It looks like it is 64 bit accoring to

http://www.cpu-world.com/CPUs/Xeon/Intel-Xeon%203%20GHz%20-%20RK80546KG0802MM%20-%20NE80546KG0802MM%20(BX80546KG3000FA).html

 

 

I know this is a few years too late for you, but in case someone else needs to know how to tell a 64-bit CPU, the simplest answer is to run Steve Gibson's "securable" program.  It'll also tell you whether the machine has hardware virtualization support, and whether it has hardware Data Execution Prevention support.  Just google for:

gibson securable

CPU-z is probably a more widely-used program.

Intel also can tell you ;)

ark.intel.com/.../64-bit-Intel-Xeon-Processor-3_00E-GHz-2M-Cache-800-MHz-FSB