Heat most certainly will reduce the lifespan of any electronic device
Sure, if I toast my logic board at 140 C like the interior of my car EMU, it will die. But the questions here are "How much" heat and "how much" lifespan.
Running your logic board components at 55 C is
way within their specification range. Components don't even blink at 55 C. Heat won't MATERIALLY affect the failure rate.
Heat and high voltage transients are the two killers of electronics. Keep both at the absolute minimum possible for maximum life.
No, the killers of electronics (laptops) are
- obsolescence
- user damage (droppage, Coke)
- mechanical, especially for laptops hinges
- LCD and peripherals
- HDD
- batteries
- then, I guess, electronic failure of which logic board failure is a part
Heat is not the dominant failure mode of your Mac, as ayeying says
If you bought 100 Macs on Day 1 and cooked them for 3 years (~1000 days) 10 hours a day, say playing WoW, that's 10k hours. At the end of that time I expect that 90 of them will still be working, 6 will have been damaged by the user, 2 will have other problems and 2 will have logic board failure. If a repair costs $300 the average cost of logic board failure is 300 x 2 / 100 = $6
over 3 years.
If you then go and install magic fan algorithms, cooling pads and other snake oil, suppose you can reduce the 2 logic board failures to 1 (I doubt it would make anything like that much difference but let's assume so). The saving to your average Mac user is 300 x 1 / 100 = $3 over 3 years or
about $1 per annum.
Let's compare with other costs of ownership
- WoW fees $13/month x 36 months = $468
- broadband fees $20/month x 36 months = $720
- depreciation say 50% over 3 years = $600
- electricity 60 W for 10k hours @ $0.1/kWh =
$60 just of electricity.
So the total cost of ownership is over 3 years is >>$1000 of which $1 is insuring against heat related logic board death.
So let's get this straight, worrying about the potential cost of heat induced logic board failure is pointless.
(a) it ain't gonna happen, heat will not kill your logic board, everything is peachy inside and
(b) the cost to the average user of fixing it is tiny
even compared to the cost of electricity to run your Mac