What's the bottleneck when FPS is below my refresh rate but CPU & GPU load is well below 100%?

[Fuzzy_3D]

I've noticed in a few games that my frame rate is way below my refresh rate (say 70fps of 144hz), but the CPU & GPU are both between 60-80% load. Any obvious limitations I'm missing?

I'm running some ancient hardware here, 2600k & 3770k both over 4.4ghz, Z77 chipsets, 16gb DDR3, SSD, 1080Ti, Windows 7 x64.

I know, I'm lucky it's still running at all , just curious if/what specifically is holding those frames back.

 

[Denpepe]

Is the CPU load the total or each core at 60 or 80%? You can have one core pegged at 100% and others at less and get an average of 80% in monitoring software.

 

[Armenius]

"A few games"
You're gong to have to be more specific than that.

 

[Fuzzy_3D]

Is the CPU load the total or each core at 60 or 80%? You can have one core pegged at 100% and others at less and get an average of 80% in monitoring software.

Is there a good way to see core saturation? Task manager distributes everything across threads so it's hard to tell.

Might try disabling a core and seeing what happens to load & FPS.

 

[Denpepe]

HWinfo64 can show you lot's of things.

 

[Fuzzy_3D]

HWinfo64 can show you lot's of things.

Thanks for the suggestion, but all I could find for CPU usage is a text version of the task manager . Wish it could show combined-thread saturation per core.

I think you're right about single core load though, noticed in Witcher 3 that a dip in GPU load usually corresponds with a spike in CPU usage.

Then I disabled Hyper Threading and the CPU started to choke, barely dipped below 90%. I think all that overhead I was seeing before was just from the unused HT "cores".

Toms has a good core scaling bench for Witcher 3, and beyond 4 cores, performance actually comes down a bit.

 

[M76]

I've noticed in a few games that my frame rate is way below my refresh rate (say 70fps of 144hz), but the CPU & GPU are both between 60-80% load. Any obvious limitations I'm missing?

I'm running some ancient hardware here, 2600k & 3770k both over 4.4ghz, Z77 chipsets, 16gb DDR3, SSD, 1080Ti, Windows 7 x64.

I know, I'm lucky it's still running at all , just curious if/what specifically is holding those frames back.

If you're playing with vsync on that's normal.

 

[gamerk2]

Is the CPU load the total or each core at 60 or 80%? You can have one core pegged at 100% and others at less and get an average of 80% in monitoring software.

An extreme case: On an 8 core CPU, you could have a load distribution of 100-0-0-0-0-0-0-0 which would report 12.5% CPU utilization, but you would have a clear CPU bottleneck. What matters isn't total load, but individual core distribution.

(As an aside, this is why Bulldozer was such a horrible CPU architecture; lots of weak cores is not the answer for this exact reason).

 

[Fuzzy_3D]

An extreme case: On an 8 core CPU, you could have a load distribution of 100-0-0-0-0-0-0-0 which would report 12.5% CPU utilization

That's the problem, my 4 core CPU with HT disable, running a single core Cinebench test shows the load distribution as 25-25-25-25 in the task manager, I'm looking for a tool that shows the true per-thread/core saturation as 100-0-0-0.

Otherwise 25-25-25-25 could also mean you have 4 bottle-necked threads each running at 25% load waiting on your GPU, RAM, SSD, etc.

 

[naib]

Are all of these online games? this points towards some form of network lag.

 

[admiralperpetual]

I mean, 1080ti is definetly going to be CPU bottle-necked by a 2600k or 3700k.. by how much and if it's worth upgrading is up to you. I'm sure my 1070 would be faster with a newer CPU but I can't swing it at the moment..

 

[gamerk2]

That's the problem, my 4 core CPU with HT disable, running a single core Cinebench test shows the load distribution as 25-25-25-25 in the task manager, I'm looking for a tool that shows the true per-thread/core saturation as 100-0-0-0.

Otherwise 25-25-25-25 could also mean you have 4 bottle-necked threads each running at 25% load waiting on your GPU, RAM, SSD, etc.

You also could have software locks; in the case you give, it looks like you have four threads that are trying to keep the workload even between them, so what is happening is each thread occasionally comes to a stop in order for the others to load balance the work.