OK, I really did not need a new computer in 2008, yet how could
I resist a quad AMD 3GHz with 8GB of RAM?

Hmmm? I can upgrade to a 12-core in 2010 (see below)

                                                  includes ship and tax
Quan  Item                                              cost
2     AMD 64 FX-74 makes Quad Core 3.0GHz 1GHz FSB      $619.98
      ADAFX74DIBOX  Socket F 1207FX
      www.tigerdirect.com

1     ASUS motherboard L1N64-SLI Dual L(1207FX)         $312.13
      NVIDIA 680a SLI MCP SSI (Holds quad core)
      www.newegg.com

4     2GB DIMM DDR2-5300 667MHz 240 pin 1.8v            $650.98
      www.crucial.com

1     ATX GAMER CASE SP21-XP 01C                        $155.40
      SunTec power supply ATX-680W
      Omega Computer, Dorsey Road

2     SATA 300 320GB 7200 RPM hard drive                $119.98
      www.tigerdirect.com

1     NVIDIA 7900GS PCIe graphics card                  $169.99
      www.tigerdirect.com

2     Plextor dual layer DVD burner                     $211.96
      PX-810SA/SW-BL
      www.tigerdirect.com

5     IDE 4 pin power to SATA 15 pin power cable         $30.93
5     1.5ft SATA II cable
      www.directron.com

total for four 3GHz cpu's with 8GB RAM               $2,271.35

(Planned on using my existing printer and display)
But, was in Circuit City with low willpower:
1     Eclipse II Illuminated Keyboard                     69.99
1     WIN TV HVR 1600 with DTV                            99.96
      (I need something to do while solving 20,000
       equations in 20,000 unknowns)
1     Indoor amplified DTV antenna                        34.99
1     USB Optical mouse                                   39.99
1     Internal Floppy                                     15.96

                        Updated total with tax        $2,508.55

Then power supply went out. Now I found I needed 28 amp of 3.3V
35 amp of +5V and 40 amp of +12V minimum. Thus:
1     Silverstone OP 1200 ATX12V power supply            380.53
      35 amp 3.3V, 50 amp +5V, 90 amp +12V

                Further updated with tax and shipping $2,889.08

(Using dual boot 64-bit Vista and 64-bit Debian)

Four years ago an 4 cpu AMD cost over $10,000


Then, 2010, for bigger PDE consulting, a 12-core upgrade

1     Supermicro motherboard H8SGL-F for 12-core AMD  $  260,18   
      socket G34 1944 pin, ATX

1     AMD Opteron 6172 12-core 2.1GHz, socket G34      1,009.00
      12MB L3 cache, 12-512KB L2 cache,
      quad channel 1.8GHz memory

1     AMD Opteron 6100 socket G34 heatsink                39.80

8     2GB DIMM DDR3 PC3-10600, Crucial  16GB RAM         805.52

1     500GB Segate Hard Drive ST3500641AS, Best Buy       63.59
      Now over 1TB, 3 operating systems  

                          total 2010 upgrade cost     $2,178.09

Reused case, power supply, fans, hard drives, DVD,
cables, etc                                              949.15
               total, approx, if all built 7/2010     $3,127.24

(HP will sell you a similar system for about $10,000)