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I have a good machine (core i7) with excellent benchmark results on number crunching.
At times, and particularly during the first quarter after boot, it is dead slow though. When I say dead slow I mean response to a simple mouse click taking 10 seconds, and applications taking ages (minutes) to launch.
But when I look at the Task Manager, there is no significant CPU activity, memory isn't saturated, no significant disk nor network activity. Of course dozens processes, but most of them completely idle.
After 30 years of career as a programmer, including system programming on many machine types (down to the level of device drivers), I thought I had a good understanding of how computers work.
But here, I am clueless: what's the computer waiting for?
[I am not after a solution nor advice about the kinds of cleanup one could do. I also don't want to get into the details of the configuration. I am under Windows 8.1, but that's unimportant, I observed similar phenomena on other PC's with other Windows versions. My question is about the mechanisms that keep the machine so slow despite no apparent activity.]
Harry Cover
Posted 2017-08-02T20:09:50.527
Reputation: 160
Guesses: Check for high CPU Temperature. Check HDD S.M.A.R.T. data for a failing drive. Check Event Viewer logs (specifically System). – Steven – 2017-08-02T20:16:30.147
Do you have an HDD, or an SSD in this machine? I am sure you have looked into it already, but a vast majority of the time this is caused by the HDD head seeking around the disk looking for files. Open Task Manager, and look at the Performance tab, in here, click on you C: drive. The main thing to look for here is
Average response time. – Matt Clark – 2017-08-02T20:18:58.757After a quick look at the SMART data, all diagnostics read OK. Average disk response time is on the order of 50 ms (I'll check again at the next boot). What puzzles me is that the slowness is transient, but systematic upon boot. – Harry Cover – 2017-08-02T20:31:08.170
@MattClark: do youmena that the machine could just be waiting for the system (hard) disk ? During these slow boot periods, disk activity is lower than later when the machine has recovered reactivity. – Harry Cover – 2017-08-02T20:34:16.920
1I think you should update your post with this information – Dave – 2017-08-02T20:34:35.517
@MattClark: sorry, I was completely wrng about disk activity. It is intense during this boot period, with Average reponse time exploding to values 10000 ms and above (?!). what's the meaning ot this parameter ? – Harry Cover – 2017-08-02T21:09:04.267
I suspected :) On boot, you need to load hundreds of files from all over the platters of the disk. HDD's are mechanical drives, in that there is a head that must physically seek to a specific location on the disk before it begins reading each specific file. This statistic is the average response time from when a request was issued to the drive, and when the drive actually responds to that request. If you need to load say 300x files, and your average response time is 1000ms, that is 5 minutes of wait time on the disk. Check your startup applications, or get an SSD ;) – Matt Clark – 2017-08-02T21:12:19.600
@MattClark: I am loading no monster at startup (except Windows), and the memory usage remains absolutely stable. Is the average response time understood per file ? – Harry Cover – 2017-08-02T21:20:27.760
Windows itself is a monster. Booting my windows laptop with a 5400 RPM HDD just took ~4 minutes from login until my HDD activity began to go down and the system became usable. The number given is not per file, but an average. Two requested files could be on the disk and loaded sequentially and have a seek time of 0ms, then you could be flooded with requests all at once as a new program starts up, now the head has to go find them, this will take longer then 0ms. The time shown in task manager is the average since the last update. Use something like CC cleaner to check you startup processes. – Matt Clark – 2017-08-02T22:59:02.333
In many modern PCs, the spinning disk hard drive will almost always be the performance bottleneck. Solid state drives can be orders of magnitude tster because they are non-mechanical; the time to fetch the next file is the number of clock cycles it takes to change the address. – Matt Clark – 2017-08-02T23:02:02.290
try chkdsk /R c: from an administrative command prompt. – cybernard – 2017-08-03T02:58:39.247
As cybernard suggested, your hard drive might be going bad. Chkdsk /r will do a physical surface scan. Bad clusters would reveal a problem. Also, has the hard drive been defragmented? Don't defrag before doing chkdsk, or you risk making things much worse. Your hard drive should never have those kinds of delays, I don't care what you are doing. – Appleoddity – 2017-08-03T05:29:16.477
@MattClark: you say 300 files @ 1000 ms takes 5 minutes, that should mean that the ART is 1000 ms per file, right ? Or is it per block, per page, per MB, per whatever ? Contiguous blocks will involve no seek penalty, but files aren't necessarily contiguous, are they ? – Harry Cover – 2017-08-03T06:47:54.273
Processes that heavily consume disk on startup sync and backup tools (Crashplan, DropBox, Google Drive). They usually start work directly after a reboot, which means scanning the disk for changed files. Stupid IMO, they should wait 3-5 minutes before doing this. – Jan Doggen – 2017-08-08T12:08:31.933
If you want to solve this mystery. Go and download Windows Performance Toolkit https://developer.microsoft.com/en-us/windows/hardware/windows-assessment-deployment-kit Then take a boot trace with WPR. Here is a tutorial in my blog https://zinetek.wordpress.com/2015/12/16/how-to-use-wpr-to-record-boot-sequence/ When done share the boot trace and I'll interpret the result for you. Regards,
– None – 2017-08-08T11:56:10.180