Why does a processor seemingly run slower as it ages over years?
November 13, 2011 12:41 PM   Subscribe

Why does a processor seemingly run slower as it ages over years?

I've noticed over the years that a well used computer processor starts to run slower as it grows older. It also starts to make that ultra fast clicking sound as it processes. I do not believe this is a mental trick: the unconscious comparison of using a new machine VS old machine. Is there a keyword to this sort of circuitry decay?

Let us assume that the computer is quite adequately cooled; is it possible to overwork a computer? I do lots of intensive renders with Maya, After Effects, and Fractal programs and I've always wondered if the wear'n'tear of these heavy computations is damaging over the course of several days without a break. I would be curious to know how long render farm services keep their blades for.

A number of years ago, I remember a specific instance where I was addicted to WoW (yeah I know...) and I was using a Powerbook 15' single core. WoW ran beautifully for a few months and then things started to slow down. Now the machine definitely and permanently runs slower. Since it is a laptop, I believe it was getting slightly too hot over long periods of continued use. In this case, I would be curious to hear from the overclocking crowd: when processor overheats and is damaged... What technically happens? What element of the processor is damaged beyond repair?

But even still, I have a PC from around 2000 and it definitely is not chugging as it used to. It was never left running full steam for days at a time.

So with my mindset shared, is it possible to overwork a processor when it is adequately cooled?

Hopefully a few of you are just as curious as I am. I've wondered about this for a few years and thought askMeta might just be the key!
posted by supyo to Computers & Internet (21 answers total) 4 users marked this as a favorite
It isn't getting slower. Your expectations are changing.

(Sometimes it is getting slower because of an accumulation of cruft, and if you were to wipe it and reinstall the OS, it really would seem faster again. But usually it's a case of your expectations changing.)
posted by Chocolate Pickle at 1:05 PM on November 13, 2011

It seems unlikely to me that this is a hardware issue; I would expect that if you were to wipe the hard drive and reinstall the original OS on one of these systems it would run just as fast as when it was new.

A previous thread on the subject of computers getting sluggish over time. My analogy is that it's like barnacles building up on the hull of a ship; every program you install puts its tendrils into various parts of the OS, modifying and adding extra steps to the internal processes or needing to change a default, optimized-for-speed setting to be compatible with itself or gobbling up little bits of memory (or large bits, depending on how badly it's written.) After many many installations it all just adds up and the drag becomes noticeable.
posted by XMLicious at 1:05 PM on November 13, 2011

The CPU itself doesn't run slower(*) but the software installed tends to get bigger and more complex. Over time you install or update software, drivers, and Windows itself. These add registry keys and extra tasks running in the background that use up memory and take processor time. For instance, iTunes installs all sorts of background processes that take up CPU time and memory. Virus scanning has also become more invasive over time.

That clicking sound? That is almost certainly the hard disk continually loading stuff. This probably means that you are running out of physical memory and the OS is forced to page things out to disk. It is also possible that the hard disk is failing, but if that is the case then your machine only has weeks to live.

You can get back to the old performance by completely wiping the computer and reinstalling the old software from scratch. But then you miss out on the new features that have introduced in the last 10 years.

* Not quite true, modern processors can run slower if the cooling is not quite working, but the window between "running a bit slow" and "shutting down now because I am about to burst into flames" is slim.
posted by AndrewStephens at 1:07 PM on November 13, 2011 [5 favorites]

In general - it's extremely rare for any computer to become slower due to any type of circuit decay or "wear & tear". The reasons a computer might be (or seem) slower is due to a number of factors - for example:

* Components made of moving parts are subject to failure. A hard drive which is physically failing might begin to respond slowly or produce errors (that must be corrected) before failing entirely. Computer fans might fail or lose effectiveness due to dust/physical wear, in which case the CPU must compensate by slowing itself down to produce less heat (upon replacement of the cooling component, the CPU would run at full-speed again).

* Installed software can drain resources, and the OS itself is generally not perfectly capable of keeping itself optimized over time. Therefore unless you know how to maintain your system properly (making sure your disk is not fragmented, making sure you have enough free space, keeping your machine free of adware/spyware/trojans, managing the programs that run in the background, etc), it will begin to slow down over time unless you occasionally reformat your drive and reinstall your OS and apps.

* Viruses, Trojans, etc can often cause a computer to perform more slowly, as can a poorly written anti-virus or internet security application.

* I'm sure some component of it could be psychological as well. Computers can often seem slower after using a faster machine, and so as time progresses it's natural that you'll spend more and more time on relatively faster computers.

There is one instance in which heavy use of a non-moving electronic part can cause it to gradually slow down - solid state drives. But these problems have been mostly mitigated by advances in the technology, so this is something that you're unlikely to experience in real-world usage.
posted by helios at 1:09 PM on November 13, 2011 [2 favorites]

I remember working with a software developer a few years ago; a developer's system is often especially bad with the accumulated bits and pieces of program cruft because they often have to install lots of different tools, program libraries, and experimental stuff.

We set up a VMWare virtual machine for him with a fresh install of Windows XP in it and he was flabbergasted because you could see them side-by-side, with the fresh OS responding two or three times faster than the worn-out crap-riddled host.
posted by XMLicious at 1:19 PM on November 13, 2011

Another way this can happen is if the hard drive hasn't been defragged in a long time.
posted by Chocolate Pickle at 1:28 PM on November 13, 2011

Yeah, this is almost always because you've got a bunch of shit installed on your computer that's slowing it down. Wipe your hard drive, reinstall windows, it'll be good as new.
posted by empath at 1:59 PM on November 13, 2011

Response by poster: Fascinating! Your replies gave me a few solid googling directions and I found some interesting links.

To be clear, I'm not trying to make this ancient machine faster. I know that you all are responding because this is the context that people are generally asking for. But I want to understand the technical background of what is possible with processors and their continued use; just as a thought experiment. Join me! I have outlined below my findings.

On the old machine of question: new hard drive, ram replaced, freshly installed windows XP (what was originally installed when first bought), cleaned of dust, not connected to internet, and it still runs slower. And its not my physiological expectations; I remember certain programs definitely running much smoother. I believe that something got overheated or old at some point and is slowing the system down. Perhaps on the motherboard.

While this may be obvious to you all, this video helps me to understand that even if the processor is slightly overheated beyond a certain threshold, then things will start to slow down.

Here is some fascinating information into the technical theory. Even though it does not practically affect performance.

--- Technically, yes, due to increased thermal noise due to an effect called electromigraton which thins out the tracking in the semiconductor material, but the effect is so minute that for all practical purposes it can be ignored. Source

--- No, the CPU runs at a fixed clock speed as determined by the BIOS and/or motherboard configuration. A build-up of dust on the CPU may cause it to overheat, which can eventually result in it locking up or failing altogether, but there will not be any gradual reduction in clock speed. It is theoretically possible to have a CPU based on asynchronous logic with no fixed clock which could run as fast as the temperature would allow, but they are not used in any consumer machine that I am aware of. Source

--- More
posted by supyo at 2:18 PM on November 13, 2011

All the reasons given above are correct and the most likely reason for perceived decrease in importance.

But..the hardware is probably getting a bit slower as well. Here's some background cribbed from here:

There is an electrical/electronic process called electromigration where the ions in a conductor drift over time and cause circult paths (both in silicon and to a lesser extent in copper tracking) to degrade and this may cause signal paths to slow down. The effect is sped up by heat and thus hot, overclocked systems can suffer more from this phenomenon.

Another issue is heat - as heatsinks and fans/vents get clogged with dust, their cooling efficiency goes down and hotter digital electronics run slower due to increased thermal noise in the signal paths - this is especially true of processors and RAM so keeping things clean and re-greasing your CPU heatsink for maximum heat transfer can help.

posted by iamscott at 2:19 PM on November 13, 2011

World of Warcraft automatically grabs the latest updates when you play, so you are not playing the same game as you were years ago, you are playing a game with noticeably higher graphics processing demands.
(They go through and up-res the levels of details as the norm for baseline hardware improves over time).

That should explain one of the symptoms anyway.
posted by -harlequin- at 2:29 PM on November 13, 2011

With all of those other steps it seems worth it to go one more and replace the processor too to confirm your hypothesis, if you can scrounge up an equivalent to the original.
posted by XMLicious at 2:33 PM on November 13, 2011

To be clear, I'm not trying to make this ancient machine faster. I know that you all are responding because this is the context that people are generally asking for. But I want to understand the technical background of what is possible with processors and their continued use; just as a thought experiment. Join me! I have outlined below my findings.
No, it is not possible for the CPU to run more slowly as it ages. The computer's speed is controlled by an oscillator, that runs at a fixed rate. Back in the old days (around 486) the oscillator was a separate component that you could remove and replace in order to overclock the machine.

The oscillator runs at a fixed rate that won't change over time, but modern computers allow you to adjust the oscillator through if you want too. But it won't adjust on it's own as it gets older. You have to do it manually. If you want to see exactly how fast your CPU is running you can use a program like CPU-z.
While this may be obvious to you all, this video yt helps me to understand that even if the processor is slightly overheated beyond a certain threshold, then things will start to slow down.
That's not true of all CPUs, particularly older CPUs. So the older it is, the less likely it is to have speedstep or something like that. You can use coretemp to monitor the actual CPU temperature as well.

Finally, it actually is possible for very small circuits to decay over time for various reasons. But in that case, the chip will just stop working. One example is the connectors on GPUs having problems due to thermal wear, which you can fix by baking your GPU. I also remember hearing about a design flaw in an Intel chipset (sort of a support chip that manages peripherals) that caused the some of the SATA connections to 'wear out' over time, due to a glitch that got introduced when the feature size (the size of the transistors and wires in the circuit) shrank. But it didn't slow down, it just stopped working. You also have thinks like nickle whiskers and stuff like that.

To summarize: Chips can wear out and stop working in some cases, but they can't slow down. They will run at the speed they are set to run at. Some chips (particularly newer ones) are programmed to slow down in certain circumstances (over heating or low battery, whatever) in which case they should slow down in those circumstances, but that has nothing to do with age.

If you want to know the clock speed of your CPU, check it directly.
posted by delmoi at 2:57 PM on November 13, 2011 [2 favorites]

Most CPUs ratchet down to a lower speed when they get hot.

As a computer ages, dust builds up, fans wear down, and it generally becomes a hotter place for a chip to be.

So the CPU doesn't actually lose any of its speed--but it might perform slower by design.

Also, check the thermal paste. This is something you smear on the bottom of the heat sink to make it touch the CPU everywhere it can. It dries out eventually. Reapplying it might make the machine run cooler and therefore faster.
posted by LogicalDash at 4:30 PM on November 13, 2011

The electromigration stuff is a reason for the older CPU to generate errors, but to do so while operating just as fast as ever.
posted by NortonDC at 4:37 PM on November 13, 2011

Another thing occurred to me: the design engineers at computer manufacturers are often carefully selecting and finely tuning the components that go in an OTS desktop and doing all sorts of testing. If you've replaced as many components as you say you have maybe you've introduced some kind of low-level problems that are producing collisions or synchronicity issues, or maybe the new components and the old components have compatibility issues, that produce the sort of slowing you're perceiving.
posted by XMLicious at 6:22 PM on November 13, 2011

Processors don't click. If you are hearing clicking, that is the hard drive. If it is frantic clicking, you have too little memory, too much stuff running or the hard drive is going bad.
posted by gjc at 6:38 PM on November 13, 2011

XP demands constant attention.

I have an 8 y/o box, and over time, it runs faster since I tweak the hell out of it, eliminating un-needed elements in the OS. I have maxed out the RAM, tweaked the display to minimze eye-candy bullshit, defrag/optimize the hard drive, and I don't chase application upgrades (like MS Office) that give me ever more unused options.

I type, code, browse, view and my machine runs fast enough that upgrade hasn't crossed my mind. In fact, I hope for a fatal failure monthly so that I can buy a Mac and be done with Winders.

If you have a gazillion apps, a full, slow hard drive, less than 3GB of RAM, a huge ass display with all eye-candy activated, a slow network... yada yada, it will be less that zippy. Geekness is useful to expunge the delay demons, but not all folks want to see their computer naked. It's pretty unattractive there, and mysterious.

Fast new computers are nearly free if you need one. For $500/year, you can have a new one annually these days.

Slow as the thing may seem, it still is waiting on input from you about 99% of the time.
posted by FauxScot at 12:45 AM on November 14, 2011

I will agree with others that generally speaking hardware parts don't get slower. With that said, your computer has power management software in them that can turn off the hard drives, dim the screens and slow down the CPU all in the name of saving electricity and maximizing battery life. If your power management settings are different now than when you remembered you could see a difference.
posted by mmascolino at 6:08 AM on November 14, 2011

The CPU itself doesn't run slower(*) but the software installed tends to get bigger and more complex.

This has always been the case. As we've trended toward's Moore's Law on the hardware end over the decades, software has become much more complex as well...enough to where it runs "comfortably" on the newest processors. As speeds increase in the future, software developers will find ways to take advantage of these performance enhancements to the point where the software is feature rich and runs "well enough" for current technology. The caveat being not as well on older systems, otherwise we'd still be fine with our 386/16 workstations of yore. Youtube has some fairly telling demonstrations of this in action. For example, take this boot comparison between a 1987 Mac and a 2007 Windows Vista Laptop. The laptop is 20 years advanced on the Mac, yet takes considerably longer to boot to a usable desktop. Why you ask? Software complexity. The Mac did not need to load much into memory in order to be usable. Not to make this a Mac vs PC statement, the same would likely occur between a 286 Windows 3.1 PC and Vista or 7 on a brand new PC.

On the other side of the spectrum, running some of that older software takes some serious clockspeed tweaking in order to run on today's processors. This is where "slowing" utilities like Mo'Slo and DOSBox come in handy.
posted by samsara at 6:27 AM on November 14, 2011

Oh, and to supyo: There are plenty of reasons your PC in particular might be running slower than before that are not necessarily processor related. You might want to check more into the following areas for possible causes:

- Chipset drivers (much more influential on overall performance than most people realize...this usually includes HD controller drivers, but they are sometimes a different inf)
- Video drivers (another performance factor)
- CPU/heatsink temperature (intels in particular have historically had thermal protection which will ramp down cycles)
- IRQ allocation with PnP (this was called Plug'n'Pray for good reasons....not all devices behave well when sharing IRQs)
- HD fragmentation
- Startup services (including Antivirus, indexing)
- Service Pack status....by SP3 XP became notably more complex than XP's original release. Albeit you lose out on features and compatibility when running the original XP.
- Physical memory and virtual memory (once physical memory runs out and the PC starts using virtual memory, there is a drastic slowdown)

In short really, the perceived slowdowns might be hardware related if components are failing or wearing down....but in many cases software/drivers/etc can play just as major of a role. Hope that helps!
posted by samsara at 6:43 AM on November 14, 2011

I recently rejuvenated some older (6+ year) Windows XP boxes. Just uninstalling programs made an appreciable difference in the speed of the systems. The problem is 99% at the application level. The hardware is stable and ready to shred bits but the applications are fragmented and hogging resources as if they are all the only program on the box. Blame the programmers, not the hardware designers.
posted by dgran at 7:14 AM on November 14, 2011

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