check if you have packet loss

Does your game stutter when you repeatedly open the scoreboard? I had the same problem but restarting my computer fixed it.

what kind of cpu temps do you have?

Do you use a FPS cap?

I've experience this issue in 2 different ways, FPS caps for some reason on gaming laptop from 6 years ago, and on a few other PCs were the cpu temps would fluctuate from 80c to 60c.

try running the command

"ping -t www.google.com"

if you're on windows. ive seen this issue before if you're on wifi, where basically no packets transfer for a fraction of a second every few seconds and all action in game stops. if that sounds like what you're having, you should be able to catch them with that ping command. note that it pings every second so it'll likely take a few cycles to catch it, and you should be able to see a spike to 200ms. net_graph 3/4 should also show a fat hole in the graph too i think

I will try that and report back. Just use net_graph 1, right?

Doesn't seem like it as anything to do with the scoreboard. I mean I do open it a bunch, but not excessively and it doesn't seem to get better/worse the more I open it.

CPU rarely even goes above 45c. Not using a FPS cap except the 300 one that MM enforces for some reason.

I'll give that a go. Just for clarification: is this a test to see if there are problems with my internet connection or is a fix for bad internet?
I'm not on wifi btw.

Ok so I tested if I have packet loss and the net_graph said "loss: 0" all the time, so I guess I don't.
Choke was at 0 most of the times, climbed to 3 rarely.

Also tried the "ping -t www.google.com" thing. It just gave me a ping for every person on the server. Didn't see anything higher than 60ms after trying a bunch of times.

The ping command goes in your Windows command prompt not the game console. Note that you will have to manually stop the ping command if you use -t with ctrl+c or pause it with ctrl+break. If it works correctly you should start to see a bunch of pings, the "time" is what you're interested in. It should become apparent quite quickly if you are getting ping spikes but I would think that if this were your issue it would show up on net_graph too.

Ok so I tried that and let it run for a minute and it always stayed at 30ms (31 once).
Or do I have to let it run in the background while on a server?

What graphics card are you using, and have you checked for or installed any firmware updates lately?
Have you tried removing any custom configs or huds? Just run vanilla everything, and see if that fixes the problem.

I'm using a GTX750Ti, latest drivers.
Haven't installed any firmware updates. Should I? You mean for the graphics card?

I've tried removing my HUD and only used my autoexec.
I felt like it helped a litte, but didn't fix the problem completely. And I'm not even sure it really did anything, since the problem is worse in some matches than in others, so I can't really be sure if the improvement was just coincidence.

I'll probably try removing all my cfg files tomorrow. Was holding back on that one so far since it's always a pain in the ass to redo all my binds.

Edit: Wasn't there a command to revert everything to default (config wise) without removing the files?

Edit2: Ok so I just tried removing all config files and resetting everything to default (no custom HUD or mods either).
Didn't make any difference. Still not sure if removing the HUD made one, but config definitely didn't do anything about the problem.

Ok so by now I'm like 99% sure that most of the stuttering only happens when I'm using a custom HUD.
I realized that the notes for the recent update said:
"A few HUD files were updated, so don't be surprised if some elements break, or all of it breaks
wiethoofd informs me that they shouldn't crash (provided your HUD uses the hudanimations_manifest setup), but who knows. He's got a detailed breakdown of the changes on huds.tf"
https://www.reddit.com/r/tf2/comments/54tjy6/tf2_update_for_92716_92816_utc/?st=ito4d97w&sh=76e06e71

So maybe the reason that the stuttering got worse after this patch is because my HUD isn't compatible with this update?
I'm using using toonHUD btw: http://toonhud.com/user/noxie/theme/MV1ECIAB/
But no idea what about the HUD might cause the problems.
Can someone recommend me a good HUD that definitely works with the new update?
Really can't stand the default HUD, especially the tiny little damage numbers.

Something else I notices is that my console gets spammed with this line:
"Failed to load sound "vo\null.wav", file probably missing from disk/repository"
Pretty sure this is new.
Could this have something to do with the stuttering?

Have you tried capping your fps?
60 monitors = max_fps 121

Do you use flashing crosshair?

Actually with the issue I had the ping counter would just freeze, probably cause any packets sent during that stutter drop and aren't retried by the game nor any intermediate router/hub

Are you using Windows 10? I had the exact same issue yesterday after the most recent TF2 update. Consistent fps drops down to 50 or less in 1-2 second intervals exactly like you described. I restarted my PC, checked my CPU and GPU temps (they were completely normal) and everything else you could think of but nothing worked. I also tried removing my custom HUD to see if that would fix it but nope, was still stuttering all over the place.

I then remembered windows had been bugging me the past 3 days about installing the latest windows 10 update. So, out of ideas, I went and installed the update. This fixed it completely. No more stutters or anything, just constant 250+ fps like I've always had.

So yeah, if you have windows 10 and haven't installed the latest update, try that :)

Problem with that is that I have a 144Hz monitor, so I'd have to cap my FPS at 288, which I don't get consistently.
Also, I mostly play MM and in MM the FPS are capped at 300 and you can't change it.

I don't.

I do use windows 10, but it installs updates automatically (don't even know how to disable that, just one of many reasons I dislike win10).
But it installed a new update just now, so I'll try if that changes anything later.

GPU temps could be a culprit as well.

Bad/conflicting drivers. I just recalled an incident I had with BF4 that after updating my drivers the older drivers didn't fully uninstall and was causing a conflict.

could try http://www.guru3d.com/files-details/display-driver-uninstaller-download.html and then install the latest driver (or one of your choosing if the latest driver has an issue)

My suggestion could be entirely placebo but I'm certain it had an effect for me.

I felt the same thing as you, like my game was smooth but it could be better, little micro stutters and things. I tried everything to fix my fps: changing configs, removing hud elements and crosshairs etc.

The one thing that fixed it for me (I'm fairly certain) was getting a new mouse. My old intelimouse must have been on its way out because when I got a new mouse my game felt smoother, those micro stutters felt removed.

Another thing I'm kinda thinking affects it is, as others have suggested, internet. My game felt incredibly smooth all lan but returning home to my less than brilliant internet definitely made my game feel less smooth.