How does the bottleneck work?

Last night I watched a couple of videos where a man named Michael Brown talked about bottlenecks in a system. Full of curiosity I went home and checked my system. Sure enough, my GPU Evga 1080 was running at 90 to 100 percent while my lazy no good CPU (i7 8700k) sat at 16 to 20 percent load… What the hey?
For informational purposes my v ram was at about 80 % while my PC ram was seeing 12 GB of use out of 16 GB available. So no need for 32 GB. This is all shown in Task manager.
What does this mean? Will SLI help? Is my Card so weak? I see good performance and great eye candy. I’m not rushing to get a RTX… FO SURE… But wanted to know what you guys think of this.

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A bottleneck is just the weakest part of the system, so if you think about it there will always be one, even with the most powerful PC on the planet.

What is getting ‘worked’ on a PC is a lot dependent on what’s running. Most modern games will push the GPU as hard as possible, meaning that things like shaders and things that run on the graphics card can cause the CPU to sit quietly waiting for things to do.

Conversely, a lot of older games or flight sims like to work the CPU harder than the GPU, in that the CPU is maxed out on a single core while the GPU waits for things to do. If you look at that 20% load, it might be the case that 1 out of 8 cores you have in your CPU is at 100% while the others are sat idle. That’s more about how the code written for the CPU doesn’t take advantage of the ‘threads’ within it rather than any inherent unbalance in what hardware you have.

So, it it normal to have a bottleneck and it is really dependent on what’s running. If we’re talking about DCS or X-Plane then a good GPU will only get worked with a high single core clockspeed CPU (and even then it won’t 100% use, as that percentage is across all physical cores). If we’re talking Overwatch or Rocket League then the GPU will be maxed out and the CPU will be sat idle mainly because the CPU doesn’t have that much to do.


I checked a lot of DCS ram thread in ED forums (wanting to upgrade my 8gb ram) and saw that the more ram you have the more DCS will use it and the less it will swap… So for big missions having 32gb can give you a little advance over 16gb…

my 2 coins!

is there a way to check how much you are pushing that core???

In Windows 10, the task manager (ctrl-alt-del or right mouse button menu on the task bar at bottom) will have a ‘Performance’ tab. The top entry on the left will be CPU, and once selected it will show a graph per logical processor or a percentage summary if you have a lot of cores.


At the bottom you can see a link called ‘Open Resource Monitor’ which leads to a more detailed tool where you can see the load per physical core.

On Windows 7 the Performance tab is further along and always just graphs:



Not that I need it but I tried to upgrade from 16gig to 32. The system simply wouldn’t take it. It would run the two new sticks alone just fine. Of course it runs the two old sticks just fine. And two sticks will run fine in any of the four slots. It won’t run all four nor a pair with 1 old and 1 new. All four are identical Corsair sticks with identical speeds, latencies, voltages, etc. Its not a big deal unless Amazon refuses the return. But just goes to show how finicky these systems can be.

Does your motherboard support that much RAM, @smokinhole? Another thing to take into consideration.

Then again…

Still wouldn’t make sense. Are all the timings the same?

Its also operating system dependant as well as mobo dependant. I bought 2 extra sticks to upgrade to 32 gig and found our my operating system (win 7 home) could not take it. Upgraded to win win 10 which could.

Just to be clear to everyone else out there, this isn’t a WIndows 7 vs Windows 10 thing, this is a 32bit vs 64bit OS thing, versions of which exist for both. Part of your decision to upgrade your RAM should be whether or not your OS can support it.

Eh you are partially right but that is only for the 4GB limit. And you could not even play DCS on a 32-bit OS so not really relevant for most here.

Windows 7 actually does limit you to 16GB, see here

So @Bogusheadbox is right

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Well then, shame on Microsoft.

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In response to @near_blind, perhaps I should have been more clear. My particular problem was not with 32bit or 64 bit OS’s (win7 comes in both 32 and 64 bit)

It was the fact that WINDOWS 7 HOME 64bit only allows you to run a maximum of 16gig of ram. Where WINDOWS 7 PRO 64bit allows up to 32 gig of ram.

I didn’t see the reason to pay to upgrade from win7 home to win7 pro when I could upgrade for free to windows 10 home which accepts 32 gig of ram. That is the only reason I chose win10. It was a free upgrade.

As an edit, and back on topic. I have noticed that if your GPU has more ram, then 16 gigs will be fine. Talking with others that have 16gig of ram and a graphics card with 11 gig of ram, they could easily run a heavy map in dcs. My old graphics card is very limited in ram by comparison and hence it struggled with trees on caucuses and heavy maps, and my jump to 32gig made it playable again. (well playable within the limits of my graphics card.)

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I was running 32 Gb DDR4 of RAM. When I built the new PC, I did not realize that it only had 4 slots for memory. I put half my memory (4 sticks) on the new PC and left the old one with 4 sticks. Now they both have 16 Gb. I don’t see a need to upgrade at this time. Every time I run DCS it uses less that 14 Gb of memory. So I will stay.
If anyone is serious about performance, I see NO REASON to still be on Win7. This is me talking, I am always the last to change OS.
I just noticed that 1080ti is going for 800 plus dollars in Amazon… Maybe because nobody wants to pay for a 2080ti.