Does Temperature affect performance?

I voted "no" because it does not have a direct impact. In a cooler environment more OC'ing is possible. The only way there will be an effect is if the computer is running at temps that are throttling, or damaging components, in this case cooler temps would increase performance by not damaging parts, but other than that it would increase longevity on OC'd parts. I run my PC in my basement because of space, I don't think it will make a very large difference however.

this one made me laugh a little. i know plenty of friends who think stupid things are computers and are to stubon to ambit different.

heat only affect the performance when it gets so hot that the motherboard start throttling the CPU to cool the system down.

on the over hand you can overclock further if the compeonts are cooler, but that assume that he has overclocked so far that heat is the barrier.

however if i had a 24/7 server i would put itin the coolest least used place in the house, because coolerparts last slighly (slightly) longer.

Unless throttling get's into the picture, temps don't affect performance.

Ok, here is the thing:

In theory even the slightest of temperature rise will affect performance, even a 0.0001oC rise will make an electronic component slower. That is because all the design and materials behave under Ohms laws and specifically the one that says: R=px(l/s) and V=I*R, hence increasing the temperature, you increase the resistance of the electron flow through the "pipes" or electron channels that make your CPU or other electronic components.

Now in reality, a 10oF, with no throttling involved will only make that computer 0.00000001% slower. You can imagine that this is not even close to traceable. But IF you could perform the exact same tests (impossible unless you have a time machine!) on the exact same PC with the exact same temperatures and all the rest variables, maybe you could see difference in the PI calculations, probably yielding you a 0.000000001% faster result.

So the bottom line: In theory it affects it. In practice, the effect is so small, it is negligible.

So your friend is basically right (in theory), but in practice you are right because the difference is so small that is almost zero. Hence you are both right, ask your friend to accept the reality (physics is nice, but you have to consider the applications in the real world as well), and you learnt a physics lesson!

it does not run quicker period. If you think it does then you need to sell your computer as you do not deserve the right to own one.

It does however run more reliable as there is less resistance to wear down the components.

Huge difference.

About the only time I could see 10c affecting performance is if the computer was already running close to maximum temps and the extra 10c pushed it over the edge. Yeah, it might affect an overclock as well, but not everyday performance.

Aside from theoretical lowering in performance due to increased resistance at higher temperatures, it also tend to cause more calculation errors and lowering stability. Although your PC hit minor errors all the time and recover instantly without you noticing anything. This takes a toll on performance, but nothing remotely noticeable. The system would've crushed long before performance loss from this effect makes a dent.