The aforementioned article doesn't specifically apply to overclockers, it's targeted towards the unintimidated that need to solve overheating issues, or desire improved stability & MTBF's.  I would agree that polishing is on the extreme-side, all for vanity.  The only requirement is that the final product be flat.

I note that if one wanted to see the degree of contact a H/S & CPU make, one could use a layer of cheap H/S paste (or Prussian Blue??? - i've no data on it's permanency) on either CPU OR H/S instead to gauge the degree of contact actually occurring, without voiding any warranty.

Don't forget work-gloves.

"don't try this at home kids"

When it comes to air cooling, avoid CPU coolers that do not cycle air towards the motherboard.  They do nothing to cool the components that power the CPU.

One item of note is the Integrated Heat-Spreaders built into most CPU's.

  Beware that use of the following technique will void a System/CPU's warranty,
           not to mention any identification marks upon it!
It is good to write the CPU spec# on the side with a fine marker after a good Isopropyl wipe, then clear-coating it.

The following article on how to lap a CPU show how to eliminate this problem.
http://metku.net/index.html?path=mods/lapping/index_eng

Note the unevenly-colored areas.  The copper-colored areas are the regions that made the most contact.
Lap your heat sink (what's the sense in doing only one & not the other) & use a premium heat sink paste (AS5 or-better, Micro-Diamond is the latest) to complete the 'mod'.

  I concur that 5-10°C improvement is average.

  Most pro-grade models have rechargeable RTC batteries, some have disposable RTC batteries.  The disposable RTC batteries (usually a Lithium coin-cell CR-prefix, except Dell) must be replaced if voltage falls below 2.85V @ 20°C.  Some OEM's use a Lithium coin-cell with leads.  In this instance, i salvage a small coin-cell socket from a dead motherboard & wire the old-cell's leads to it & then find an electrically-insulated (non-thermal-zone - 40°C max) place to mount it with a common hot glue-gun.   I check with a handheld WiFi detector that runs on Lithium coin cells (if it can't light up the cell is a dud).  This shows that each cell can handle a standard load.  Rechargeable RTC batteries (ML-prefix) usually require 16-24 hours to fully recharge from a discharged state.

I have personally seen a dead RTC battery cause a black-screen issue on at least one notebook.  Usually a bad RTC battery will simply cause the time to be reset, yet other affects may occult your best efforts.

If your main battery has little capacity even after a full charge, discharge it using Memtest86 (or similar), charge it to full, then repeat 2 more times.  Ensure that it is stored between 5°C & 40°C (preferably 20°C) as these battery-type's lifetimes are reduced at 'extreme' temperatures.  Never attempt to charge a battery that is outside that temperature range!

Generally speaking, electronic components are engineered to last 1.5 times their original warranty length.

Look to clean the equipment if it does not have burst capacitors in them.  https://secure.wikimedia.org/wikipedia/ … tor_plague

Dust can carry electrostatic charge, and particles of magnetite & other electrically conductive particles.  Use the utmost caution cleaning power supplies internally as they can store a charge even after the cord has been pulled.  Simply hold down the Power button for 5-10 seconds after pulling the power cord to remove most of the excess charge (use caution anyway if you do open 'em up).  Compressed air (limit to less than 80psi or less for safety reasons) and a clean soft Nylon brush are good methods of "Dust Bunny" removal if you don't mind the "cloud" of dust.  Avoid breathing the dust; use a cartridge-type personal air filter at a minimum.

Dell may have shipped more affected systems than others.  http://techreport.com/discussions.x/19178

Even brand new capacitors have a lifespan limited by a number of factors.  They are generally rated at 105°C for a specific number of hours.  Every 10°C decrease in temperature doubles their minimum lifespan.  A capacitor rated for 2000 hours @ 105°C could be expected to last 64000 hours @ 55°C, or 7+ years!  This is conditional upon the amount of "Ripple Current" supplied from the power supply and the capacitor's rated Ripple Current capacity.  (Some mistakenly believe that replacing caps is easy, yet there are dozens of differently engineered types; interchange is not for the novice!)

If you want a good-quality Audio Amplifier, you would want one with a top-quality power supply to avoid EMI & other factors that affect the quality of audio output.  A computer power supply could be thought of in a similar light.  We all want our bits & bytes with no distortion!

I like using 2000-grit sandpaper to lightly burnish alloy connectors (for PCI cards & memory); unlike gold connectors, some alloys tarnish over time.  Connectors should be cleaned with 99% IsoPropyl Alcohol & a clean cotton rag.  Avoid breathing the vapors & use nitrile gloves.  Beware static discharge whilst handling, it's flammable!  Use anti-static precautions to protect your hardware, anyway.

Memtest86 is a great ISO to verify that your machine's memory isn't immediately failing (linked below).  One pass is good for most machines.  If your memory is that bad (or an incompatability) it might not POST.  Best to test with memory in it's intended configuration & backtracking if problems are found.

I like the Video Memory Test, too.
  Homepage --> http://mikelab.kiev.ua/index_en.php?pag … AMS/vmt_en   Download ISO --> http://sourceforge.net/projects/vmtce/files/

Special notes for Dell Optiplex GX-270, GX-280, SX-270, SX-280 desktops & GX-520 or GX-620 SFF power supplies.  http://www.thecapking.com/gxgxcais.html
Samsung & Dell Display owners need look here --> http://www.thecapking.com/lcdrepair.html
Note:  I do not personally endorse this company, i'm just linking for the information contained within.