How To Identify A CPU Bottleneck - Is Your CPU Bottlenecking Your GPU? 

Very good and interesting video, glad to see more people explaining things! We're going to make a video about this, but I will now add some of you case scenarios here and show your channel as well

One easier way to see when you have a CPU bottleneck, is to use process explorer to examine the individual threads of the game. Cyberpunk will run dozens of different threads, but not every aspect of the game engine is multithreaded, and the scheduler will move some of those threads between various cores rapidly depending on the load (perfectly normal when a game launches 100+ threads. If you look at the individual threads, you will often see 1 thread using 1 core worth of CPU time, and at that point, frame rates stop improving. A simply test is to use settings that that get the GPU usage in the 85-95% range, then while gaming, downclock the GPU (e.g., lower it by 500MHz in afterburner), that would get the GPU to be pegged at 100% while also lowering frame rates, ensuring a GPU bottleneck). then gradually increase the clock speed of the GPU while looking at the threads in process explorer. You will notice a gradual increase in frame rates that will stop as soon as one of the threads in the game reaches 1 core worth of CPU time (to figure out what is 1 core worth, take 100, and divide it by the number of threads available by the CPU, including hyperthreading. For example, a 16 thread CPU would allow for up to 6.25% of CPU time representing 1 core worth of CPU time. Since a single thread cannot use more than 1 core worth of CPU time, that thread will have encountered a CPU bottleneck. PS, a system memory bandwidth bottleneck is very rare, the only time I have been able to replicate one in a modern system, was when a lower VRAM card, e.g., 8GB or less, and in a game where the engine did not disable the use of shared memory. Once shared memory is in use actively (you can tell by the PCIe bus usage increasing significantly, and once it hots 50%indicating saturation in one direction, you will notice a scenarios where both the GPU and CPU is underutilized. PS, in those cases, you can get small boosts in performance by tightening the timings of the system RAM to improve the latency. as with modern cards, they typically have around 25GB/s DMA access from a PCIe 4.0 X16 bus, but in some cases where full saturation is not reached, lower latency minimizes how much performance is lost while shared memory is in use. Once full saturation happens, then frame times will become very inconsistent and the game will hitch/ hang as well. A storage bottleneck, will show dips in both CPU and GPU usage (most easily seen as simultaneous drops in power consumption).

Gosh, I really need to pay attention when typing as I constantly make typos. Apologies for typing "Scenario" as "Scenarion" 🤦‍♂️

Love these vids!

Great video. Very informative and enjoyable!

A faster way, or used in conjunction with this, is to look at the gpu power consumption. The 4070 Super is a 220w card. When gpu bottlenecked, it was running under 150w.

You are amazing, your explanation is clear 😊

Very interesting. Thx mate

Shout out to my fellow South African🤙, great video buddy, very informative. I’ve been out of the pc gaming scene for a while now, so I started searching for videos before I upgrade my hardware, stumbled onto your video. Subscribed, I will definitely support your videos in the future.👍

This is a very good video!

Thank you very much.

This was an excellent video. From someone who started to understand this after getting into PC gaming 2 years ago, it's always quite jarring seeing the comments in other benchmark videos or even in steam forums such as "my system is fine because my CPU is only 30 percent utilized so it must be the game" or "why test the 4090 at 1080P" in CPU benchmark comparisons.

I cap the FPS on my GPU so it runs cooler & smoother, since FPS performance over a certain quality threshold amount is just benchmarking giggle numbers, unnecessary strain on components, & extra heat generation for my bedroom. Running a GPU at max FPS is more likely to create occasional stuttering & less-smooth play, since it has no additional overhead to handle the sudden loads that create drop-off lows. So, my R9-7900 CPU likewise is probably just jogging along with my capped GPU instead of sprinting. Works well for me.

good video mate finally understand this shit now haha

Also, even if your CPU load says 100%, that is most likely a lie. That is actually the average of the CPU’s P cores load. Meaning that if you have both the GPU and the CPU usage at 100%, you can still get a better GPU and not bottleneck it. As long as you don’t play something like Star Citizen. In that game, every single GPU gets bottlenecked no matter what CPU you have 😂

for the layman out there, if you see your GPU usage below 90-100%, then you have most likely have a cpu bottleneck. that cpu bottleneck however could be due to your cpu being underpowered compared to your gpu or it could however be due to the game/engine itself (like dragon dogma 2, jedi survivors, witcher 3 remaster)

Great video, i just had 2 questions 1: is gpubussy only for intel or can i use it for an amd cpu as well 2: when i play games I can see the buildings and signs either pop up or render slower than the surrounding area. Like a billboard's texture load later than buildings and such. And i noticed it on every game from spider man to cyberpunk and Alan wake 2. Do you think it can be a cpu issue? Btw my cpu is ryzen 5 7600 and for gpu i have a 7900 gre with 32 gigs of ddr5 ram 6000mhz. And the percentages are normal meaning gpu is 90-100 and cpu is 60-80

How did you get your MSI afterburner to display like that?

How did you get CPUbusy in MSI AFterburner/RTSS? I would like that functionality Shout out from SA BTW

Man could you help me? I need help and nobody could help me yet. I got a RX 6650XT and Ryzen 5 3600. Other people with the exact same setup or an even better GPU dont have the huge stutter i have in Battlefield 5, Battlefield 2042, Palworld etc. I tried EVERYTHING and it looks like a CPU bottleneck to me. But why do other people have a slight bottleneck but dont get stutter so the game is unplayable like mine is? Like its the same exact setup? i got fast 3600mhz cl18 ram, nvme m.2 980 pro, temps are well under the limit and my mobo is great too. XMP on, SAM / Rebar on etc...

frame gen and DLSS is gross, i want my imput lag as low as possible and my vision in "native", how to identify CPU/system bottleneck? your GPU is not running at 99% all the time, simple. (edit: well duhh there are gonna be games where 99% GPU utilization is not possible, either being a really old game with weak graphics or poor optimization. but it is still a CPU bottleneck when your GPU is not running at 99%)

Yes it is interesting subject. You can build the most expensive pc and easily still be in a bottleneck.

I have a 7800x3d paired to a 4080 OC. I am currently playing Skyrim at 1440p without a frame rate cap (a mod). And with enough mods, textures, grass mods and DynDOLOD you can absolutely see the CPU bottleneck everything. The FPS will be below the v sync 165hz cap, and GPU will be at 90% with CPU at 20%. I think it's because the game only really uses one thread. So while it seems the CPU is chilling. It's actually not able to let the 4080 go to 99% on Skyrims game engine

You can also have CPU Bottleneck even if only 1 Core hits 100%. On other side, if you play online games where you need lower input lag, its better to have CPU Bottleneck. Alternative is to Cap your FPS (or Reflex & Anti-Lag) but CPU bottleneck is preferable if you can get much higher FPS than the Monitor hz. Actually both CPU% & GPU% should be as low as possible while maintain high FPS (lower than 60-70% GPU & the individual CPU cores). Even if the monitor cant show more frames than its refresh rate, the input lag improves (higher 1% & 0.1% FPS).

hey, i have 16gb of ram, an i5 11400f, an rx 6600 xt, my fps in fortnite is generally low (dx 12, competetive settings, 1080p), the cpu gets to a 100% of usage when in the sky and i get awful stutters, i've tried optimizing, reinstalling windows, anything, couldn't fix it, do i need to upgrade my cpu, my ram, suggestions?

I have the opposite problem. After years there is still no game that utilizes my CPU.

A CPU can be a bottleneck as a result of hitting the single thread performance limit. And, technically, it is the GPU that is being bottlenecked; the CPU IS the bottleneck, in both of these scenarios.

I'm playing Cyberpunk. My CPU is at 63% usage. When I saw the video with 63% CPU usage and bottleneck. I sweat. After seeing the video. I'm safe.

But I don't understand how it got fixed at 9:55 just by disabling the upscaler????

Most times the issue is not cpu and the games its the background apps that are the issue. Like you run Discord and browser but the game already needs 100% of your cpu so it causes stutters. good example is my cpu is a i5 8600K @4.8 GHz but pubg stutters when discord and my browser is open. close it and the stutters are gone and my fps is stable at 120+ fps on 2k

Hlo brother if the intel i5 13600k had good 1% lows than amd r5 7600x in gaming with rtx 4070 or rx 7800xt then sir please tell the right answer...then should me buy intel or amd..

I know that it is a bottleneck (bad) ,but I'm not sure how bad it is. My spec is i3 6gen with 3060 12gb. And other PC is i7 8700 with rx 6800 xt.

cant unfocus from turning car

I guess my CPU is just not fast enough because my CPU usage is around 60% and my gpu usage around 60 also in games that are not that GPU intensive.

Interesing video. I'm thinking about upgrading mi 13400F with 7900XT and get an used i7 i9 but ryzen path sounds tempting.

The second scenario was a RAM speed bottleneck, not a CPU bottleneck. I don't think it's helpful to call this a "CPU bottleneck".

Oh my God 😱, I clicked at 666 views 💀

🙂 i find the topic a liitlw bit confusing, and on utube the topic causes trolls in the comments shaming people with old hardware combinations

Slower RAM bottlenecks to.

Them Estrogen cores holding back this CPU. 🤣 On a more serious note when you benchmark for a couple hours or play some shooter at 300+ fps you want that gpu hitting 100%. When you want to enjoy a game for like 12 or 16 hours at a stable 125fps or 90fps or 60fps lock you want your gpu to have some headroom and to not use maximum power. So the GPU usage and power usage are fluctuating lets say from 60% to 95%(or 40% to 80% or 70% to 90%) depending on whats happening on screen at the moment, but your framerate is stable 125 fps and frametime is a flat line at 8ms.

mb

Oh God, watching this entire video is painful Someone else did a better job at maximizing the Balance between P & E Cores and causing RTX 4070 at 100% GPU usage. Here's your mistake 06:14 it has been proven countless times that you shouldn't be gaming using both P & E Cores simultaneously. You can get much higher FPS Than this entire video and also maximizing RTX 4070 Super at near 100% usage using this exact same CPU. Here's how. Step 1. You are not supposed to disable E Cores at all because You will be assigning E Cores for Windows itself and all other background tasks Step 2. You should assign CPU Affinity of only P Cores for the game itself by deselecting E Cores before you launch the game. Step 3. After you did Step 1 and 2, now Windows will automatically have tighter timing because it doesn't need to reach out to E Cores for the game Process. You are NOT Supposed to do like 03:36 Because it means All Windows tasks are also using those P Cores. If you did it correctly, all 6 P Cores will be at 99% Usage most of the time, and all E Cores will be at idle but not disabled, and E Cores will still be visible by MSI Afterburner. HINT: Cyberpunk 2077 Game Engine is fully optimized at 12 CPU Threads. That means 6 P Cores equals 12 Threads. Excluding all E Cores. Anything beyond 12 Threads isn't counted as "Bottleneck" at all. It is counted as "Performance Leak". Don't believe me? Feel free to look for CDPR documentation about Parallelism of CP2077 Engine. it is really Optimized at 12 Threads. After you locked the game to use only 6 P Cores, while NOT Disabling any of E Cores, your FPS will be much higher than this entire video. And you will also see RTX 4070 Super nearing 100% Usage.

Pretty Long and Over Complicated Video for a Simple Matter Really.