I have a Kill-A-Watt Power meter on my computer that has a GPU mining bitcoins. It draws 500W from the wall outlet.  My question is, is my computer outputting any less heat than an equivalent 500W heater? Or is 100% of the power drawn from the wall converted into heat?  I'm not sure where the energy would go, so my gut reaction seems to say yes. However, the computer is performing other operations with the power, flipping transistors and spinning fans and such. Would it have some less-than-100%-percentage of the power input that is converted to heat then?  If the fans and hard drives and other kinetic components were excluded (say 500W with nothing spinning, all solid state), would it then have the equivalent heat output of the 500W heater or a perfect 500W heat source?
I am trying to find a good rough guesstimate of how much of the maximum wattage usage of a graphics card is turned into hot air.  Say a graphics card is rated at using X watts at maximum usage. How much of that is released as heat into the air via the cooling setup, and how much is not (If not where does it go? To ground?)  Yes I know there are a lot of variables here, I am just looking for a guesstimate from someone who would understand better than me. I'm specifically using  (Radeon 6990 375 watts max)
Linux: coloring bash prompt will break carriage return When I try to colorize the bash prompt like this:  export PS1="\e[0;31m[\u@\h \W]\$ \e[m "   it breaks the carriage return (instead of going to a new line when line is full, it starts in the same line and erases the input text).  If I remove the color sequence it works fine. I use Ubuntu 11.10 and terminal (guake has the same bug too). After hours of banging my brain against my skull, I narrowed down an issue I'm having to the fact that \makeatletter doesn't work inside \newcommand. Commands that I call after \makeatletter are registered as undefined, as if \makeatletter didn't do anything.  Why is this the case?  In the example below, I define two commands. Calling one of them from the document body causes the undefined error, while the other doesn't.  \documentclass[11pt]{book} \usepackage{kvsetkeys}  \newcommand{\commandThatFails}{     \makeatletter \comma@parse{}{} \makeatother }  \makeatletter     \newcommand{\commandThatWorks}{         \comma@parse{}{}     } \makeatother  \begin{document}  Hi there.  \commandThatFails \commandThatWorks  \end{document} Does visiting Canada from USA under ESTA reset the visa waiver? Find all $n\in\mathbb{N}$ so that there exist $x,y,z\in \mathbb{N}$ that solve:   $$(x+y+z)^2=nxyz$$   I tried to attack it finding solutions, but all the solutions doesn't seem to have something in common. For example:  $$ (x,y,z,n)=(1,1,1,9)$$ $$ (x,y,z,n)=(1,2,3,6)$$ $$ (x,y,z,n)=(1,4,5,5)$$ $$ (x,y,z,n)=(2,2,4,4)$$ $$ (x,y,z,n)=(8,8,16,1)$$  I was trying to solve this problem, but someone told me that a hint to solve it is using Vieta Jumping. I don't know how to use Vieta Jumping, so can anyone help me to understand how to apply Vieta Jumping and solve the problem? how does systemd determine service is stopped? I have a Gary Fisher bike (wahoo I believe). I think it's considered the entry level Fisher mountain bike.  Could I put on disc brakes as opposed to using the standard  brakes on this bike?  Standard brakes are the rim brakes.   Thanks Carlos How are parentheses interpreted at the command line? Is there any way to tell Google to use a particular account for all Google services by default? I typically use 2 Google accounts simultaneously in my browser. So whenever I fire up any Google service like Google Maps or YouTube or Google Search, it uses one of the accounts. The problem is that I don't want that account to be used and no matter how many times I switch the account for these services, they seem to default to same account.  Is there any way to tell Google to use a particular account for all Google services by default?    I am not talking about using Google account to sign in to third party websites. I am talking only about Google's own services.  I am using Chrome if anyone is going to suggest client-side solution. I'd like to be able to tail the output of a server log file that has messages like:  INFO SEVERE   etc, and if it's SEVERE, show the line in red; if it's INFO, in green.  What kind of alias can I setup for a tail command that would help me do this? Evaluate $\lim_{n \to \infty} \int_{0}^1 [x^n + (1-x)^n ]^{1/n} \ \mathrm{d}x$ Seeking Mobile Data collection software recommendations? Number of ways to choose $n$ balls from $3n$ balls, distinguishable/indistinguishable. Does $\sum\limits_{k=1}^n 1 / k ^ 2$ converge when $n\rightarrow\infty$? I can prove this sum has a constant upper bound like this: $$\sum_{k=1}^n \frac1{k ^ 2} \lt 1 + \sum_{k=2}^n \frac 1  {k (k - 1)} = 2 - \frac 1 n \lt 2$$ And computer calculation shows that sum seems to converge to 1.6449.  But I still want to know:  Does this sum converge? Is there a name of this sum (or the series $\frac{1}{k^2} $)? Is it possible to exit the airport without going through the customs? I'm looking for a 90s (or early 2000s) scifi (mini)series where a boy and old man chase a black guy in metal suit. I think they were going through different dimensions. I remember part of it, but I don't think I ever saw how it ended. I remember my friend telling me there was a twist at the end. I think they were trying to find something and he was always ahead of them.. Inequality: $ab^2+bc^2+ca^2 \le 4$, when $a+b+c=3$. Why does the natural ring homomorphism induce a surjective group homomorphism of units? I'm trying an old problem here:   Suppose $n\mid m$, and I have a natural ring homomorphism $\varphi\colon \mathbb{Z}/m\mathbb{Z}\to\mathbb{Z}/n\mathbb{Z}$ defined by $\varphi(j)=j\mod{n}$. I can verify that this is a ring homomorphism, but why does it induce a surjective group homomorphism on the unit groups $(\mathbb{Z}/m\mathbb{Z})^\times\to(\mathbb{Z}/n\mathbb{Z})^\times$?  My question in particular is why is it surjective? I take $k\in(\mathbb{Z}/n\mathbb{Z})^\times$. Then there exist integers $s,t$ such that $sn+tk=1$. Since $n\mid m$, I can also write $m=na$. So multiplying through I get $sm+tka=a$. I'm lost here. How can I find a unit in $(\mathbb{Z}/m\mathbb{Z})^\times$ which maps to $k$ to show surjectivity? Can you use the /testfor command in minecraft 1.8 to find out if a player has died ?  I need it for my map, where 2 players (Only) are pitted against eachother. I want it so that when one of them dies, it will detect the death and declare the victor. Drush PHP syntax error when running I am following the instructions to install Drush that are listed on this page:   I seem to be getting a syntax error within the code:  [user@localhost ~]$ wget https://github.com/drush-ops/drush/releases/download/8.0.0-rc4/drush.phar --2015-11-16 16:23:02--  https://github.com/drush-ops/drush/releases/download/8.0.0-rc4/drush.phar Resolving github.com (github.com)... 192.30.252.131 Connecting to github.com (github.com)|192.30.252.131|:443... connected. HTTP request sent, awaiting response... 302 Found 2015-11-16 16:23:05 (1.47 MB/s) - drush.phar saved [3496991/3496991]  [user@localhost ~]$ php drush.phar core-status  Parse error: syntax error, unexpected '[' in phar:///home/user/drush.phar/includes/output.inc on line 188   I am not seeing this error on Google. Any idea how to fix it? For mathematics, is it ever disadvantageous to use \left(  and \right)  in equations?  I can't see any way that doing this would hinder the typesetting, so why isn't () just converted into \left( \right) automatically? This would save a lot of typing.  Cheers!