downloads gradually slow in speed then stop

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Dezarius
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downloads gradually slow in speed then stop

Post by Dezarius »

I've had this issue as of late seemingly out of nowhere, as I haven't made any changes to anything. Downloads will gradually slow down in speed, until it hits 0. Sometimes torrents added barely gain any speed at all, before slowing down to zero. It varies how long a torrent will download for before it happens, as well as when a torrent starts off with high speed and when it starts with slow speed and just fizzles out right away. The random pattern is making this very confusing.

I've tested 3 different hard drives, and the issue is the same. I've also tested 2 different torrent software, same thing. I've yet to check with my ISP, even though I don't see how it would all of a sudden be an issue when I've downloaded fine with the same ISP since 2009. Could it even be the PC itself? I've seen mentioned a few times about RAM, how does that figure into this, if at all? I've been trying to find a clear pattern to it for days but it seems to happen randomly, but will always go back to slowing down then stopping torrents, even if you might download for a bit or even finish a torrent here and there. It's not an issue of seeds and such, I use a private tracker and there's plenty of that. I even get the high speeds as expected but the torrents always slow down and stop after a while, so you're just depending on random luck when it wants to work or not.

There's other small things here and there I've noticed lately, like if you choose to exclude a part of a torrent file, say you only want to download 1 episode out of a season pack, the torrent will always gradually slow and stop, doesn't matter how many files you choose to download, as long as you exclude even 1, the download stops. Allocating more bandwidth to one file will also cause it. The first time the issues started was actually when I tried to do just this, which has never been an issue before. Sometimes pausing a torrent will make it not start again as well. It almost seems as if any action will piss it off, like "don't touch me", lol. I'm not even doing anything that should be an issue. I thought that could be the client but again, tried Deluge as well as my main which is qBit.

Some extra info. Like I said I've tested 3 different HDDs interchangeably and it's the same issue, but I'll just add this for context if nothing else. Before these current issues, and the 3 HDDs I've tested, I also earlier this year had a HDD that I had used for years dedicated to torrents, break, from some freak glitch. I added a torrent like always and everything just froze. The whole computer, couldn't do anything. Turns out it couldn't even be plugged in because the OS would not load properly if it was, everything would just freeze. We couldn't recover it, and I had it replaced earlier this year. The new one has worked OK until now. There has been some hiccups which I've noticed here and there, but I didn't want to be alarmed before there was a clear consistent issue. Would be things like the disk seeming to struggle with writing at times, torrents getting errors, media player lagging if downloading at the same time, client freezing up. I couldn't think the new HDD would be faulty as well, so I just passed it off as it's just your typical flukes.

The issue that caught my attention thinking something is wrong was download speeds started spiking unnaturally, not due to standard fluctuations. They would go high, then drop lower gradually, then shoot back up, and this would not stop. It affected heavily on download times so I found it not viable. Shortly after the final issue started with torrents slowing gradually then just stopping. Just to make sure I returned this HDD as well, got a new one, but the issue is still there. I also tried with a backup drive that I have lying on my shelf, same thing. Logically it shouldn't be about the drives then. I can only think it could be the PC and so every drive will eventually break or have issues. Or it's totally unrelated that the first drive of several years broke using torrent, and that I'm having other torrent issues across 2 new HDDs after, and on the old backup drive. You tell me.

If I can provide more information do tell, I feel like I'm not good at giving the technical info succinctly, so I apologize if this was a long ramble and not making the issue clear.

UPDATE: After torrents have gone down to zero for a while, they start again if left be, but eventually drop to zero again, and so on. I've been paying most attention to download but I just realized I'm getting no upload speed at all, no peers connect they just disappear again.
Last edited by Dezarius on Tue Jul 26, 2022 10:09 am, edited 1 time in total.
unseen19
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

Hi,

The ISP, the ISP route, or the computer so. This is not the half of a scope.
About the ISP I guess forum with others on the same one can give you the answer
What if you restart the ISP router/modem during a download? does the speed come back?
On the computer side, the RAM or swap may be the root cause. You need to monitor the memory consumption at first in the task manager
The pressure on the disk (queue depth is what you're looking for) can be displayed in the performance monitor (taskmanager>performance tab>link en low left of the window)
Dezarius
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

unseen19 wrote: Mon Jul 25, 2022 9:35 am Hi,

The ISP, the ISP route, or the computer so. This is not the half of a scope.
About the ISP I guess forum with others on the same one can give you the answer
What if you restart the ISP router/modem during a download? does the speed come back?
On the computer side, the RAM or swap may be the root cause. You need to monitor the memory consumption at first in the task manager
The pressure on the disk (queue depth is what you're looking for) can be displayed in the performance monitor (taskmanager>performance tab>link en low left of the window)
Memory use seems fine. The disk use spikes to 100% when the issue occurs (download speed drops), then back to normal use when speed is stable. Memory does register "Hard Faults" though. As I read: "Hard faults often occur when a memory block has to swap to the virtual memory (hard drive or SSD) instead of physical memory." Could this be the case?
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

The disk is not fast enough to handle the download speed it seems. If so the IO request will be queued and your memory will be involved, resulting with the symptoms you exposed. The system will then use the swap and, worst case, the swap may have a foot on the same disk leading to more load.

Let's start the easy way and limit the QBT speed to something low: 10MBps for example. With this download limit in place how is the behaviour?
Dezarius
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

unseen19 wrote: Tue Jul 26, 2022 12:57 pm The disk is not fast enough to handle the download speed it seems. If so the IO request will be queued and your memory will be involved, resulting with the symptoms you exposed. The system will then use the swap and, worst case, the swap may have a foot on the same disk leading to more load.

Let's start the easy way and limit the QBT speed to something low: 10MBps for example. With this download limit in place how is the behaviour?
What do you mean by the "swap" ? I'm also curious why this would be a problem when I've always downloaded at the same speed (max) without any issues, so it doesn't make sense why the drive would not handle it. My max speed is actually 7MBps (VDSL). This behavior is recent, and is happening no matter what drive I use. I tried anyway, limiting speed to 4MBps behavior is still the same.

Whenever issue occurs the disk stops writing, speed drops, disk starts writing speed goes back up. Upload speed is at 0 always, I noticed.

I checked with the ISP and connection should be fine. I also reset my modem, checked Firewall and disabled Anti-virus program. No change.
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

With a download speed of 7MBps any drive is fast enough. You mention multiple drives tests so it's not the device attached.
Is the computer hardware and setup healthy by all means? The computer behaves correctly when used for other purposes?
What is the version of QBT and the settings changed?
Dezarius
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

unseen19 wrote: Fri Jul 29, 2022 11:03 am With a download speed of 7MBps any drive is fast enough. You mention multiple drives tests so it's not the device attached.
Is the computer hardware and setup healthy by all means? The computer behaves correctly when used for other purposes?
What is the version of QBT and the settings changed?
The computer is healthy overall, the problem only shows in regards to torrent. QBT version 4.4.3.1 (newest). I tried 3-4 older versions to check if the issue was mended, but same thing. No settings was changed in torrent or the PC, nor the connection. Which is why I don't understand how this problem started when nothing has been changed from when it was working.

I changed to "pre-allocate all files" in QBT but only after the issues appeared, as a means to try and fix it, it didn't but I left it enabled. I also changed some system power settings for harddrive, but again only after the fact. I'm not sure if the power settings only apply to system disk, or all drives including externals, it doesn't really specify. But as I said issues presented before changes to any settings, it was just to troubleshoot.

Power settings were "Turn off hard disk after" which was always at "20 minutes", I changed to "Never" to see, no difference, changed back to "20 minutes" default. "Allow hybrid sleep" I can't remember default but it's "Off" now. "USB selective suspend" is "Disabled".

I think we agree it is not a hard drive issue, and I just find it very strange and not make sense how this problem has happened without anything being changed. My PC is mainly used for torrents, and things are running as always, same program, settings on Qb and PC. I mostly leave it be as it usually does its job, works fine. No hardware changes. Running on same connection since 2009, almost never issues and very stable.
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

You may have mentioned it but it slipped out of my attention: the destination disk is an USB drive, correct?
This introduce more variables (firmware, enclosure controller, etc.). But a recent change occurred in Windows regarding the removal policy of the removable drives. The way the cache is used my be your issue here. Disabling it first to check the result, even if such will hardly impact the performances it's a start. We are are first looking here for a behaviour change. Then the different caching option may be tested

Can you check the cache policy for the disk and test it?
Dezarius
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

This change seems to be Windows 10? I should mention I am on Windows 8.1.

Edit: I'm starting to get a strong suspicion that the source of the problem is the OS/system disk, this could explain why it seems to be hard drive related yet external drives seem to be fine. Torrents are downloading to external HDD yes, but qBittorrent program itself is installed on and running from system drive. So if system drive has fault, it could impact torrent as well?

This could also explain why issues started despite no changes being made to anything. Maybe because the system disk is failing? It is a little strange that except this the system seems fine. But could this be because the system is not really working much, except when torrent is used, this might be enough activity to provoke the problem. If we ruled out external drive, software, and connection, maybe system fault is the explanation, system disk. What do you think? It is from 2013 so quite old now.

There is another thing as well that made me think of this. I was watching a show and I heard this noise from my computer, similar to external drive working but different enough that I got up and checked it. There was no active torrents, and it sounded like inside the computer. I put my ear to external drive, it was not that. Only hard drive makes that noise, so it must be system disk. But normally my system disk barely makes a sound, it is quiet and also doesn't do any heavy work. But this was noisy, like something is failing. It was there for maybe 30 seconds.

I realize I've heard this noise 1-2 times before at different times. It was very brief, but still I don't think a hard drive should make that noise. If the disk is failing it is strange why it only made this noise a few times and very briefly. I don't want to make a problem out of nothing but I think it is worth to take this into consideration since so far we have not found the cause.

Well I guess we can't dismiss external drive as the issue either, because even if the drives are fine the PC could still cause problems in connection with external drives. I'll wait on you for what to do next.
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

Yes it will have an impact. If you're suspicious about the system disk you can try:
#check the disk (more steps may be provided if anything found by the command)
chkdsk c:

#check the SMART status of the disk with any tool, diskinfo from Crystaldiskinfo for example

#check os file corruption
sfc /scannow

If anything occurred (power outage or disk issue) these commands should tell you. In the end as Win8.1 is out of support an update will be a good move. You can even consider a linux distribution to get rid of license cost for such (...well I know :) ) with an Ubuntu for example. QBT is well supported and easy to update for this one (PPA, app package).
Dezarius
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

check disk: "Windows has scanned the file system and found no problems."

system file check: "Windows resource protection did not find any integrity violations."

SMART status: "OK", "OK".

PredictFailure status: "FALSE 0"

Seems all good.

I am definitely considering a new PC, but I must say I'm curious about what the root cause is.. :S
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Re: downloads gradually slow in speed then stop

Post by unseen19 »

all fine indeed, system disk is not involved.
have you tried a download on the system disk already? The idea is to bypasse the USB.
Alternatives are Sata or SMB if possible, or at least a different USB enclosure with a different chipset. The system disk is the easiest of course
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Re: downloads gradually slow in speed then stop

Post by Dezarius »

Testing done. Using external drive shows clear issues that using system disk does not. Using C: everything seems fine. I've recorded everything now, if you would want to see, D: vs C: use but also just the general symptoms occurring. But yes external drive / USB seems to be the problem... As for torrents I can say that torrents with multiple files seem more problematic, but that may be obvious as there's more to work with.

There is one thing I haven't mentioned, but this has been present long before these issues. Which is that when I boot up the PC, the external drive can not be plugged in. If it is, the screen will just be black. You have to unplug it to boot up. When you get to the login screen it is safe to plug it back in. I haven't cared too much as I can just unplug and boot, but worth to mention in this case. Not sure if this is related to the problem at hand.
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