Personal computing discussed

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Topinio
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Re: CPU vs GPU Bottlenecks

Wed Dec 12, 2018 3:59 am

synthtel2 wrote:
That core is probably spending very close to 100% of the time active.

Image

No bouncing around.

The issue is the system usage is across all 8 threads, presumably from the video driver, taking ~20-30% of each CPU thread, i.e. ~40-60% of each physical core. The non-system portion is about 60% of 1 CPU thread.

I need to look into what's going on, and check how it plays between DX11 and DX12, and how the v8.1 DX12 MT changes affect it.

synthtel2 wrote:
It's a lot more than a handful if you're on 2C4T. Even Skyrim is noticeably faster on 4C4T than 2C4T unless you want to run potato-level shadows, and pretty much everything released in the last 5 years is at least that threaded.

Even WoW 8 years ago was noticably faster on 6C than <6 (for AMD)
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Re: CPU vs GPU Bottlenecks

Wed Dec 12, 2018 8:21 am

Topinio wrote:
Ifalna wrote:
Well it is true for MMOs. Boh Final Fantasy XIV and World of Warcraft gobble up CPU power w/o any problem, esp when there are many people around.

Not sure about that, WoW uses only 15-26% of my CPU and 50-60% of my GPU according to Task Manager, but only gets 50-70 FPS, at max settings. (Total load is 30-40% on CPU and 50-60% on GPU.)
I don't understand this, even assuming I can near double those CPU numbers as Windows is counting threads not physical cores. It's not looking GPU- or CPU-limited.

It's not hard to explain: WoW and other MMOs are basically single threaded applications.
Yeah they manage to offload some work to other cores but alot of things in MMOs just have to be calculated in sequence. Multi threading doesn't help with that at all.
Easily seen by a tanking framerate when you have more than 40 people and live parse combat log data with an addon like recount.
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Topinio
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Re: CPU vs GPU Bottlenecks

Wed Dec 12, 2018 2:57 pm

Ifalna wrote:
WoW and other MMOs are basically single threaded applications.
Yeah they manage to offload some work to other cores but alot of things in MMOs just have to be calculated in sequence. Multi threading doesn't help with that at all.

Image
Looks a bit beter in 8.1 with DX12 MT options.
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synthtel2
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Re: CPU vs GPU Bottlenecks

Wed Dec 12, 2018 4:08 pm

Topinio wrote:
Image

No bouncing around.

The issue is the system usage is across all 8 threads, presumably from the video driver, taking ~20-30% of each CPU thread, i.e. ~40-60% of each physical core. The non-system portion is about 60% of 1 CPU thread.

How did you determine those two of the game's threads were sticking to one core, then?

Task manager's graphs are really bad at capturing things like this. Process explorer's breakdown of a process' threads and their individual CPU time would be a better tool.
 
dragontamer5788
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Re: CPU vs GPU Bottlenecks

Wed Dec 12, 2018 4:24 pm

Topinio wrote:
synthtel2 wrote:
That core is probably spending very close to 100% of the time active.

Image

No bouncing around.

The issue is the system usage is across all 8 threads, presumably from the video driver, taking ~20-30% of each CPU thread, i.e. ~40-60% of each physical core. The non-system portion is about 60% of 1 CPU thread.


That's not how CPU Utilization works.

CPU Utilization is how often a logical core is NOT running the idle thread. A single core may be using 100% of the resources of the CPU (while the idle-thread on the hyper-thread sibling may show 0% utilization). To actually know how much CPUs are being utilized, you need a profiler. The crude estimate that Windows / Linux gives you is strictly a measurement of idle-thread activity. The Idle Thread has one job: to update CPU Utilization metrics and then go to sleep for 15-milliseconds or so... maybe downclock itself if its been idle for a long time.

------

Second: "bouncing around" is quite possible in that graph. You've got a ton of logical cores at low utilization, and one core at high utilization. So "bouncing around" wouldn't surprise me.
 
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Re: CPU vs GPU Bottlenecks

Wed Dec 19, 2018 1:45 am

Depending on the game, GPU's may get to flex their muscles more if an SSD is used, especially in the minimum FPS: https://www.tweaktown.com/articles/7911 ... ndex2.html
 
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Re: CPU vs GPU Bottlenecks

Wed Dec 19, 2018 8:27 am

I suppose I've got pretty close the the "ideal" mid range CPU and high end GPU (an I5-4460 and a 1080). I'm quite happy with it for gaming at 4K on the games that interest me (mostly single player stuff).

I think these days your resolution is really the deciding factor in your graphics card. Back in the dark ages of the early 2Ks up until not long ago there really wasn't that much difference in monitor resolution, at the low end was 1024x768, at the high end mayby 1600x1200 or perhaps 1920x1080. That's only about 2.5 times the pixel count while these days we have 1366x768 at the low end and 3840x2160 at the high end which is nearly 8 times the pixel count.

You can buy a monitor that will make any gpu the bottleneck if you want to.

Do I occasionally get the urge to buy an new CPU, certainly but I'm not made of money and for me a big advantage to PC gaming is the way I can stagger upgrades. I think the first PC I ever brought is the only one I got all in one go. Ever since then I've always replaced the cpu and kept the gpu or vice versa.
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DeadOfKnight
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Re: CPU vs GPU Bottlenecks

Wed Dec 26, 2018 3:18 pm

cheesyking wrote:
I suppose I've got pretty close the the "ideal" mid range CPU and high end GPU (an I5-4460 and a 1080). I'm quite happy with it for gaming at 4K on the games that interest me (mostly single player stuff).

I think these days your resolution is really the deciding factor in your graphics card. Back in the dark ages of the early 2Ks up until not long ago there really wasn't that much difference in monitor resolution, at the low end was 1024x768, at the high end mayby 1600x1200 or perhaps 1920x1080. That's only about 2.5 times the pixel count while these days we have 1366x768 at the low end and 3840x2160 at the high end which is nearly 8 times the pixel count.

You can buy a monitor that will make any gpu the bottleneck if you want to.

Do I occasionally get the urge to buy an new CPU, certainly but I'm not made of money and for me a big advantage to PC gaming is the way I can stagger upgrades. I think the first PC I ever brought is the only one I got all in one go. Ever since then I've always replaced the cpu and kept the gpu or vice versa.

Yeah I'm not looking to upgrade yet, because even if being CPU bound sucks more, it's still the exception and not the norm. I'm kind of just waiting for the Intel vs AMD competition to level out.

Right now the competition is all about single vs multi-threaded performance per dollar, where Intel can still charge a premium for chips that offer the best of both. This won't last forever.

I predict something close to performance parity for mainstream products in the next few years, where there will be a straight up war on price rather than value for specific types of workloads.
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dragontamer5788
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Re: CPU vs GPU Bottlenecks

Wed Dec 26, 2018 4:12 pm

DeadOfKnight wrote:
cheesyking wrote:
I suppose I've got pretty close the the "ideal" mid range CPU and high end GPU (an I5-4460 and a 1080). I'm quite happy with it for gaming at 4K on the games that interest me (mostly single player stuff).

I think these days your resolution is really the deciding factor in your graphics card. Back in the dark ages of the early 2Ks up until not long ago there really wasn't that much difference in monitor resolution, at the low end was 1024x768, at the high end mayby 1600x1200 or perhaps 1920x1080. That's only about 2.5 times the pixel count while these days we have 1366x768 at the low end and 3840x2160 at the high end which is nearly 8 times the pixel count.

You can buy a monitor that will make any gpu the bottleneck if you want to.

Do I occasionally get the urge to buy an new CPU, certainly but I'm not made of money and for me a big advantage to PC gaming is the way I can stagger upgrades. I think the first PC I ever brought is the only one I got all in one go. Ever since then I've always replaced the cpu and kept the gpu or vice versa.

Yeah I'm not looking to upgrade yet, because even if being CPU bound sucks more, it's still the exception and not the norm. I'm kind of just waiting for the Intel vs AMD competition to level out.

Right now the competition is all about single vs multi-threaded performance per dollar, where Intel can still charge a premium for chips that offer the best of both. This won't last forever.

I predict something close to performance parity for mainstream products in the next few years, where there will be a straight up war on price rather than value for specific types of workloads.


I disagree. AMD may be making strides in AVX2 / 256-bit compute, but Intel is pushing AVX512 very strongly, with Icelake giving support. At very least, the future will be partitioned into AVX2 vs AVX512 performance categories moving forward. AVX512 would be useful for H265 encoding, among other applications. I'd imagine that Intel's mesh network is superior in databases and some other workloads too, compared to the split-L3 cache on AMD's Zen design.

"Single-threaded 64-bit compute" (such as what video games typically do) seems like AMD is reaching parity with Intel soon. At least, Intel hasn't made any big announcements for big IPC or clock-rate gains yet, while AMD is clearly benefiting from 7nm and higher clocks. Its a tough call overall, since Intel has been so silent on the issue. But... one would assume that if Intel actually made big strides in the lab, they'd be bragging about it by now.

So that's why I'm assuming Intel didn't make big strides in "single-threaded 64-bit compute". Because Intel simply isn't talking about it.
 
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Re: CPU vs GPU Bottlenecks

Wed Dec 26, 2018 9:39 pm

dragontamer5788 wrote:
I disagree. AMD may be making strides in AVX2 / 256-bit compute, but Intel is pushing AVX512 very strongly, with Icelake giving support. At very least, the future will be partitioned into AVX2 vs AVX512 performance categories moving forward. AVX512 would be useful for H265 encoding, among other applications. I'd imagine that Intel's mesh network is superior in databases and some other workloads too, compared to the split-L3 cache on AMD's Zen design.

"Single-threaded 64-bit compute" (such as what video games typically do) seems like AMD is reaching parity with Intel soon. At least, Intel hasn't made any big announcements for big IPC or clock-rate gains yet, while AMD is clearly benefiting from 7nm and higher clocks. Its a tough call overall, since Intel has been so silent on the issue. But... one would assume that if Intel actually made big strides in the lab, they'd be bragging about it by now.

So that's why I'm assuming Intel didn't make big strides in "single-threaded 64-bit compute". Because Intel simply isn't talking about it.

Well I was mostly talking about gaming performance. I agree there will be no "parity" as long as there is innovation. There will always be differentiation. I mean, these chips take several years to go from ideas on pen and paper to actual products.

These are different teams of engingeers with different visions of what the market will look like years in advance. They have different strategies, more focus on different market segments, and different targets on the performance vs efficiency curve.

They take different risks, invest more in different bleeding edge technologies, create new innovations of their own, take different approaches to manufacturing, and this is all further multiplied by the work of their different software development teams.

Whether they want to compete directly with or fill in the gaps between existing products, the landscape is inevitably going to look different when they finally come to market, and each of these products will have different strengths and weaknesses.

My prediction is based on AMD, after winning over console makers, hopefully recognizing the importance of PC gaming for mindshare and probably knowing what they need to improve, along with Intel's history of complacency when they're on top.
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cegras
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Re: CPU vs GPU Bottlenecks

Wed Dec 26, 2018 11:29 pm

Yes, the problem is that CPU frame time can only be decreased by upping processing power, whereas GPU frame time is easily tweaked in graphics settings. If you choose wrong with the CPU, you're out hundreds of dollars, whereas with the GPU you can always pick whatever is within your budget and make it work.
 
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Re: CPU vs GPU Bottlenecks

Thu Dec 27, 2018 1:55 am

cegras wrote:
Yes, the problem is that CPU frame time can only be decreased by upping processing power, whereas GPU frame time is easily tweaked in graphics settings. If you choose wrong with the CPU, you're out hundreds of dollars, whereas with the GPU you can always pick whatever is within your budget and make it work.

Yeah, that's exactly the point I was trying to make. It's great to buy the top graphics card available and be able to max out the image quality settings and still get smooth performance, but it feels like I raised maximum performance and not my minimum.

Even with a less powerful GPU, I could do the same and max everything, at half the fps. It's a noticeable improvement, but I wouldn't say that a whole lot of games went from unplayable to playable at max settings. Everyone talks about 60 fps like it's the minimum for smooth gaming, but in my experience there's really nothing wrong with playing a game running at 45 fps if the frame times are consistent, especially with variable refresh enabled.

On the other hand, if a game wants more from my CPU, it isn't just a lower fps. In fact, the majority of the frame times will be low, but the game can become a stuttery mess with frame time spikes. lt's like playing a game with a heavy workload running in the background, and there's nothing you can do about it. There are no settings or driver updates you can try. You can hope it's an optimization issue that will get patched, or buy a new CPU.

Admittedly, this seems to be more common for games widely considered to be poorly optimized, but my point remains if devs are better at optimizing games for GPU than for CPU usage. Need a better CPU for better minimum gaming performance.
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cegras
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Re: CPU vs GPU Bottlenecks

Thu Dec 27, 2018 6:52 pm

I upgraded my PC specifically for gaming, and jumped from an i7-2600 to a i5-9600K - not a 2700X - to get the highest minimum frames possible. It was really hard to find data that focused on the CPU bottleneck - TechSpot/HardwareUnboxed is good. I actually found a benchmark somewhere (russian forum .. game.ru??) that showed a RX480 could have played BFV at over 150 fps if the CPU bottleneck was removed, but since I was in upgrade mode I sprang for the Vega 64, and still set everything to around Medium to always stay at 144 FPS.

In BF1, the RX 480 and i7-2600 and all Low gets about 6-7 ms frame times, regardless of how busy it gets. However, the CPU frame times range from 8-15 ms, and as you will probably guess, the 15 ms is when things get busy, exactly when you don't want to be losing frames. Those frame times cannot be alleviated by any setting....
 
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Re: CPU vs GPU Bottlenecks

Fri Dec 28, 2018 4:29 am

I have an RX Vega 56 with an E3-1270 v5, and have been contemplating putting in an E3-1275 v6 for £330 rather than a £400 RX Vega 64, for this reason...
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Re: CPU vs GPU Bottlenecks

Fri Dec 28, 2018 5:33 am

Vega 56 is a pretty good GPU. If I was you I'd hold on both, and start shaving shekels for a six core CPU of some sort. More headroom for the 600,000 random processes in a typical Windows deployment, something that usually isn't captured very well in a benchmark/review rig.
 
Topinio
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Re: CPU vs GPU Bottlenecks

Fri Dec 28, 2018 2:02 pm

NovusBogus wrote:
Vega 56 is a pretty good GPU. If I was you I'd hold on both, and start shaving shekels for a six core CPU of some sort. More headroom for the 600,000 random processes in a typical Windows deployment, something that usually isn't captured very well in a benchmark/review rig.

Yeah, IK, but a new motherboard is going to be an expense and a massive faff and I CBA. Plus the cost of a new Windows licence as I'm pretty sure this one's W8 Pro upgraded to 10 won't play with a future boar, and that's a +£500 new-system fee that I don't want.

3 of my last 4 motherboards at home got a mid-cycle CPU upgrade, so I'm slightly itchy on this one now it's past the 5Y mark ... TBH, if I saw a new E3-1285 V6 kicking around at list pricing, I would have to fight myself to not jump at it.

That way, I can also keep the Vega 56 until AMD's next big GPU comes out (or NVIDIA stops failing to support FreeSync monitors)

/derail ;-)
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cegras
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Re: CPU vs GPU Bottlenecks

Fri Dec 28, 2018 4:52 pm

Topinio wrote:
NovusBogus wrote:
Vega 56 is a pretty good GPU. If I was you I'd hold on both, and start shaving shekels for a six core CPU of some sort. More headroom for the 600,000 random processes in a typical Windows deployment, something that usually isn't captured very well in a benchmark/review rig.

Yeah, IK, but a new motherboard is going to be an expense and a massive faff and I CBA. Plus the cost of a new Windows licence as I'm pretty sure this one's W8 Pro upgraded to 10 won't play with a future boar, and that's a +£500 new-system fee that I don't want.

3 of my last 4 motherboards at home got a mid-cycle CPU upgrade, so I'm slightly itchy on this one now it's past the 5Y mark ... TBH, if I saw a new E3-1285 V6 kicking around at list pricing, I would have to fight myself to not jump at it.

That way, I can also keep the Vega 56 until AMD's next big GPU comes out (or NVIDIA stops failing to support FreeSync monitors)

/derail ;-)


I bought W7 Pro back in 2009-ish, upgraded for free to W10 Pro, and re-activated it via phone after a complete hardware swap. All I had to do is give my original W7 key to the cust. support person. Registering your digital license to a MS account will not work, which is what I tried first.
 
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Re: CPU vs GPU Bottlenecks

Sat Jan 12, 2019 8:01 am

So this thread and JBI's one about going Ryzen pushed me over the edge for getting a new CPU (that and I saw one going for a reasonable price on ebay). It's not exactly an earth shattering upgrade, going from an i5 4460 to an i7 4790 but it is very much noticeable despite the actual FPS count not changing that much. I'm afraid I don't have any numbers but my purely subjective impression is that "smoothness" has gone way up.

I suppose it isn't a major surprise that a faster CPU is... faster
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