Computers are very reliable, except when they're not. "The computer never makes any mistakes" -- that's true, for the most part. But dunk your smartphone in a glass of deliciously refreshing mint tea, and it will probably make a mistake or two (or, in other words, die). Dunking your phone in a glass of tea would be silly, of course, but letting your computer run too hot can be almost as damaging, if less visible.

Just as shorting a computer out will ruin it, making it run in temperatures it was never meant to take will cause it to malfunction. SpeedFan is a free system temperature monitor for Windows designed to help you keep a close eye on just how hot your computer is getting, down to the individual component level.

First Impressions: A Lean, Clean, Classic

This is not the first time we are reviewing SpeedFan: Guy covered it way back in 2009. You'll be excited to hear that since then, SpeedFan has moved from version 4.37 all the way to 4.49, making huge strides in... well, nothing really. This tool is a classic, and it looks like one. It's a case of not fixing what isn't broken, and the interface shows few changes relative to four years ago.

An application's installer can speak volumes of its simplicity and polish. The worst offenders bundle browser toolbars and other junk trying to make a buck, while bloated behemoths often force you to run through a complicated multi-step process. SpeedFan's installer keeps things simple and has only two steps, with absolutely no junk in the process:

system temperature monitor

The only caveat to using SpeedFan is that it does require Administrator access to work properly.

Tabs and Numbers

Launch SpeedFan, and you'll find an interface that makes almost no effort to make things simple. This tool is all about the numbers:

system monitor

Breaking the wealth of information down to six tabs is a welcome concession to usability. Even so, the Readings tab is packed full of information, along with very few explanations. You can see system temperatures at a glance: Turns out my computer reports no less than nine separate readings, some cryptically labeled as Temp1, Temp2, and Temp3 -- and then there's Temp1 and Temp2 yet again, with different numbers. Others are clearer, though: I do have a discrete GPU (I use a desktop workstation), so seeing its temperature right off the bat is nice. Due to the cryptic labels, this screen is mostly useful for understanding if anything is amiss. You may not know what Temp2 is about, but if it's at 70C, that's probably a cause for concern.

Exotics: What a Tab!

I had to show this tab just because of its name. I mean, really, who can resist clicking a tab called Exotics?

At first, the Exotics tab is tantalizingly blank, save for a button labeled Show the magic coupled with a Beta warning. All of this buildup only makes its eventual output somewhat of a letdown:

system monitor

This thoroughly anticlimactic screen carries some useful data formatted into exciting rectangles. It starts out with the same temp readings we've seen on the prosaically-labeled Readings tab, but continues to display hard-drive S.M.A.R.T ratings (HD0 and HD1), as well as the utilization of each CPU core, the CPU's master clock frequency, and the system's uptime.

S.M.A.R.T: All About Your Drives

You didn't really think SpeedFan was going to limit itself to just a single number concerning your hard drive, did you? Just click the S.M.A.R.T tab to see more information than you've ever wanted to know about your hard drive(s):

system monitor

You can see the make, model, and firmware of the drive, followed by a list of S.M.A.R.T performance and health readings. Some of these prove too much even for SpeedFan, hence the "Unknown Attribute" labels. In other words, "here are some numbers, but we're not sure what they mean." To be fair, this is an SSD. When analyzing my other drive, a magnetic HDD, it did better:

speedfan system temp

Some of these metrics are cryptically named, but you can always search for their meanings online. The icons next to some of the entries offer at-a-glance health indicators: They're all OK in my case.

Charts

Last but not least comes the Charts tab. It's not as excitingly named as Exotics, but it does offer a more visual treat: 

system temperature monitor

These are not as nicely formatted as the Resource Monitor or Reliability Monitor built into Windows, but they are quite descriptive, and you can switch metrics on and off as you wish. One feature that's missing is a way to export the data into a CSV file for graphing outside of SpeedFan.

Final Thoughts: A Tool To Keep In Mind

The SpeedFan system temperature monitor is not exciting. That's not a bad thing, though: Sometimes we need a tool that's just useful, rather than thrilling. It's certainly established in its field, and is good enough to make it into our coveted list of the Best Windows Software under the eclectic Other category. You may not use it every day, but next time your computer starts acting weird and you can't figure it out using the tools built into Windows, this is one tool you can try.