>You can either get an underpowered mini for the price of a powerful Linux desktop
Have you considered the cost of electricity? Power consumption at idle on the average desktop is like 4 or 5 times that of the mini. Also the mini sleeps and wakes quickly and reliably, and probably draws less power sleeping that a normal desktop draws when powered off. (You have to either unplug the normal desktop or flip the switch on the back of the power supply to get zero power consumption.)
There's also the noise issue: an idling 2011 mini can be heard in a quiet room if you are very close to it, but you would not notice unless you are listening for it.
P.S. I am curious whether Linux on modern hardware sleeps and wakes quickly and reliably. When I ran Linux (on hardware made in the 1990s) I kept it powered on and "awake" (not sleeping) continuously because that was the only way I could always sit down and start typing. In contrast, I usually sleep my 2011 mini when I walk away from it.
Have you considered the cost of my time? My 4.7 GHz i5 desktop with a good SSD is probably at least 3 times faster to compile my project than a Mac Mini would be (even with an SSD). It's now fast enough that I don't get the urge to switch to Hacker News while waiting. If I had to pay $100 per month for electricity for it, I wouldn't care.
And I doubt that the electricity difference is major. My i5 spends most of it's time at 1.2 GHz, and I'm using an efficient power supply. So when running at full-tilt it uses a lot more power, but when just running Emacs it's basically idle.
And yes, a modern Linux desktop does hibernate properly, although sleep is a little more problematic. It also boots in about 5 seconds (although most modern PCs have horrible BIOSes that add about 15 seconds).
The current Mac Mini is supposed to pull between 10W (at idle) and 85W (at load---this is the limit of what the PSU can take from the wall.[0]
Let's be generous and say that the Mac Mini, if left on continuously without sleeping, pulls on average 20W.
Let's be pessimistic and assume that power costs you $0.20 per kWh.
# The time in which the Mini will use 1 kWh
1000 Wh / 20 W = 50 hr
# The number of hours in one year
365 days * 24 hrs = 8760 hrs
# The number of kWh the Mini will use in one year
8760 hrs / 50 hrs = 175.2
# Cost of running the Mini continuously for one year
175.2 kWh * $0.20 per kWh = $35.04
That's amazing, no? Let's say, then, that you bought a mini for $599 dollars; your cost of ownership would be 599 + 35.04n, where n is the number of years you've owned it.
No doubt impressive.
A desktop I built relatively recently, which a Core i5 and an unnecessary graphics card, along with a few hard drives, pulls roughly 60W at idle and 150W at load (measured at the outlet by a Kill-a-Watt).
Let's be not-so-generous and say my machine pulls 100W on average, is left on continuously, and my electricity costs $0.20 / kWh.
My computer will use a kWh in 10 hours (1000 / 100); and will cost $175.20 per year to operate ((8760 / 10) * 0.2).
My initial cost for this machine (excluding monitor, keyboard, etc.) was $450. SO my cost of ownership is 450 + 175.2n.
The cost of ownership for east will equal in :
599 + 35.04n = 450 + 175.2n
149 = (175.2 - 35.04)n
149 / 140.16 = n
n = 1.06 years
So after a year of ownership the Mini becomes "worth it," if power consumption if your first requirement.
Note however, that I've given the Mini every benefit of the doubt possible, did not take significant steps to minimize the power consumption of my machine, am able to upgrade my machine piecemeal instead of discretely (and thus have significantly lowered future costs of ownership), and have assumed we've been leaving the machines on continuously.
The Mac Mini, let's say, pulls 0W when in S3 sleep.
My machine pulls 1W in S3 sleep, and about 0.2W when off (to answer your query, it wakes reliably and quickly).
If we assume my machine is asleep half of the time:
Half the time (8760 / 2 = 4380 hrs), my machine pulls 1W.
While asleep, it will take 1000 hrs to use 1 kWh.
Therefore, it uses 4.38 kWh in the time it is asleep.
Which means the new yearly cost is:
(175.2 / 2) + (4.38 * .2) = 87.6 + 8.76 = 96.36
The Mini ends up costing $17.50 yearly.
So:
599 + 17.5n = 450 + 96.36n
149 = 78.86n
n = 1.889 years
Once you factor in the cost of replacing the Mini versus upgrading a small bit of my machine, I think the answer is much less clear cut.
P.S. I don't mean to pick on you, but excitement about power consumption that doesn't factor in the numbers is a pet peeve. The Mac Mini is only "worth" it if having the computer you actually want is worth less that $80 or so per year to you.
The mini can take 2 2.5-inch hard drives and (unofficially) 16 gigs of RAM. Like I said elsewhere, I do not consider the mini suitable for software development or other demanding tasks. The popularity of smartphones and tablets as ways to access the web will probably prevent web sites operators from increasing the computational demands of accessing the web so much that I will need to replace the mini in 4 years -- online selling and buying and iPhoto being the most demanding things I do with the mini.
The mini weighs 2.7 pounds. When I want to spend a couple of days at the girlfriend's place, I bring it along and plug it into her TV set. (Unlike laptops and netbooks, however, the manual instructs me to power the mini down before moving it, and I do worry a little that it is not designed to survive this weekly commute.)
The girlfriend would have aesthetic objections to my plopping most computers on her living-room floor, but the mini is stylish enough and small enough not to raise any objections.
I guess my overall point is that when you use mobile-class components, like the mini does, you can get away with having just one fan, like the mini does, which saves further electricity, since fans consume electricity, and makes it easy to avoid making noise, and make the whole device potentially very compact and light, which has its uses even in a desktop machine.
The mini can take 2 2.5-inch hard drives and (unofficially) 16 gigs of RAM. Like I said elsewhere, I do not consider the mini suitable for software development or other demanding tasks.
Software development is not a CPU demanding task by any stretch of the imagination.
Professional programmers get just fine on an Air, much more so for a Mini --not to mention with 5 times slower machines just 3-4 years ago.
Linux. S3 sleep doesn't work in Windows, for reasons I haven't bothered to figure out. I only use Windows to play games, so I never had reason to care that it didn't go to sleep.
S3 is a firmware-managed power state. The OS (modulo bugs: for example not being able to reliably enter a sleep state) doesn't have anything to do with its power consumption.
You get to choose, and can go for something between. Eg when I built my Linux box a year ago I used the lowest power Core i5, SSD, 8GB ram which is nearly silent, and uses 50W from memory at peak. Linux sleeps fine now.
Have you considered the cost of electricity? Power consumption at idle on the average desktop is like 4 or 5 times that of the mini. Also the mini sleeps and wakes quickly and reliably, and probably draws less power sleeping that a normal desktop draws when powered off. (You have to either unplug the normal desktop or flip the switch on the back of the power supply to get zero power consumption.)
There's also the noise issue: an idling 2011 mini can be heard in a quiet room if you are very close to it, but you would not notice unless you are listening for it.
P.S. I am curious whether Linux on modern hardware sleeps and wakes quickly and reliably. When I ran Linux (on hardware made in the 1990s) I kept it powered on and "awake" (not sleeping) continuously because that was the only way I could always sit down and start typing. In contrast, I usually sleep my 2011 mini when I walk away from it.