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Is my cpu bottlenecking my HD 7950?

Last response: in Graphics & Displays
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December 26, 2012 4:30:20 PM

I have 2x 7950 running in crossfire.
The CPU I have is 3770k, automatically overclocked by my ASUS z77 v LK mobo to 4.22 ghz.
I just installed the game sleeping dogs, and I was running afterburner along side and I noticed my GPU usage fluctuates every second. Sometimes it would reach 100% but it will come down to the 30% range.
I checked core temp, and CPU usage was around 40-60%.

Is my CPU bottlenecking? I read somewhere that CPU can automatically underclock itself randomly..or when it reaches critical temps.
Thing is, I have a thermaltake frio with 2 custom fans pushing 170cfm (temps never reach over 60C).
So what is the problem?

BTW gpus are not OCed. Just the factory OC to 925mhz.
CCC software is 12.10 (latest)

More about : cpu bottlenecking 7950

a b U Graphics card
December 26, 2012 4:34:05 PM

If your CPU usage is 60%, it's not causing a bottleneck. Have you installed the latest crossfire profiles?
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Anonymous
a c 117 U Graphics card
a b à CPUs
December 26, 2012 4:36:48 PM

no, it is not bottlenecking your cards; 40%-60% cpu load isn't even close.

i'd look at the drivers - but if you want to be sure; lower the settings/resolution in game play. if your frame rate goes up then the cpu is not holding back the graphics.
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a b U Graphics card
a b à CPUs
December 26, 2012 4:41:41 PM

I still don't understand why people seem to freak out so much about "supposed" bottle neck, I does happen but normally its not pronouced unless your running a sub $100 cpu with a $300+ GPU even then it really depends on the game. Anyways I hate to ask but are you having problem with FPS or did you just noticed the CPU/GPU usage and just assume there was an issue ? The reason why I ask is I see a lot post about people not getting X frame rate in a game that they saw some one else on the web got so other that than usage are you having problems with the game ?
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December 26, 2012 11:55:47 PM

Yes I'm having problems with this game. Minimum framerate reached 32fps on sleeping dogs benchmark mode. I'd assume having 2 of these high end cards would cap it at 60fps. :/ 
I thought sleeping dogs supports AMD cards better than nVidia.

What other driver is there to get besides the most recent CCC app profiles?

My other question is, is this GPU usage fluctuation normal? Is this a problem with the video cards? All the videos I watched on youtube shows 100% gpu usage all the time.

couple things I forget to mention, I'm gaming on 1080p resolution with 3dmark11 combined score of 122xx (~7500 individual performance scores).
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a c 134 U Graphics card
a b à CPUs
December 27, 2012 12:02:12 AM

Okay keep in mind that sleeping dogs kills cards on benchmarks seriously I'll give you a link to a monitor review where this guy reviews it on 1080p and 1440p. Believe me you are just fine with your card. I tried embedding it but it doesn't have the old youtube embed code which seems to be the only way to get it to work. Start around 10 minutes I promise you are fine.

http://www.youtube.com/watch?v=fbGhz01JL24&list=UU_SN80...
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December 27, 2012 12:19:11 AM

okay. Great!
But for future references, can anyone tell me if this GPU usage fluctuations are normal?
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December 27, 2012 12:38:25 AM

I ran the benchmark again and I noticed the game was only using 1966 MB of VRAM. Other people with radeon HD 7950 posted pics of the benchmark and it was showing them 3xxx MB VRAM for them...

This is the picture:




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Anonymous
a c 117 U Graphics card
a b à CPUs
December 27, 2012 1:31:26 AM

i highly doubt 3gbs of Vram was needed to run 1920x1080
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a c 134 U Graphics card
a b à CPUs
December 27, 2012 2:04:16 AM

It isn't but that game will use it loon I know its crazy but it will. GTA IV is the same way it will suck the ram out of your computer faster then you can chug a beer.
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December 27, 2012 2:27:29 AM

What is your power supply? Also keep in mind that sleeping dogs can be rather brutal on FPS, especially if you are running the HD texture pack. Your CPU is definitely not a bottleneck...such an overused word for something that typically doesn't happen.
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December 27, 2012 2:34:10 AM

its a seasonic 750w 80 plus gold.
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December 27, 2012 2:34:47 AM

bigshootr8 said:
It isn't but that game will use it loon I know its crazy but it will. GTA IV is the same way it will suck the ram out of your computer faster then you can chug a beer.

so the gpu usage fluctuations are not normal?
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December 27, 2012 2:42:04 AM

Gpu usgage flucuations are normal. If the game is badly coded, you will see your usage down around 50% or lower. I'm running 3 7970s and only get around 50% usage on far cry 3, hopefully they will patch the problem soon.
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a c 134 U Graphics card
a b à CPUs
December 27, 2012 2:42:43 AM

Yes they are quiet normal. Like dude says and far cry 3 is another game that is just heavily taxing on computers right now but yea sleeping dogs is a game that is just incredibly taxing on a computer maybe a bad port.
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December 27, 2012 2:49:35 AM

Turn the overclocking off on your CPU and see if that improves your usage and FPS. Overclocking causes increases in power consumption...minimum recommended psu for a crossfire 7950 is 700 watts, so your setup is just above the minimum recommendation. If there is no change with the overclock off, then you most likely don't have a power issue.
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a c 134 U Graphics card
a b à CPUs
December 27, 2012 2:51:59 AM

no the power supply recommendation for a 7950 is far below 700 watts. 500 watts is the recommended amount of power for that card.
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December 27, 2012 2:58:41 AM

nociception said:
its a seasonic 750w 80 plus gold.


bigshootr8 said:
no the power supply recommendation for a 7950 is far below 700 watts. 500 watts is the recommended amount of power for that card.



OP is running 2 7950s in crossfire. 500 watts will not cut it for crossfire, will work for single card.
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December 27, 2012 3:22:18 AM

He is running a decent 750 watt psu...seasonic isn't the best, but it is gold rated. Gold rated psu has an efficiency of 87% at 100% load...so assuming that the psu has not degraded, this psu would produce roughly 652 watts at 100% load.

So since the PSU is putting out 652 watts at full load, my concern is that it might not be enough. Each 7950 (stock factory clock) draws a little under 200 watts at full load. The 3770k draws about 208 watts when overclocked to 4.5 ghz (op is at 4.2 so I'd bet is closer to 190). Add in power consumption of the motherboard (cant estimate). Then add in all the other devices...usb devices (especially external hard drives that get power from usb), keyboard, mouse, hard drives etc...can't estimate this because I don't know what all the op has, but you can see that the numbers start jumping pretty quick.

So just the 2 7950s and the 3770k draw around 600 watts. Here are a few good links if you are interested.

http://en.wikipedia.org/wiki/80_Plus

http://www.tomshardware.com/reviews/ivy-bridge-overcloc...

http://www.thermaltake.outervision.com/
*note...keep in mind that the 3770 has 4 physical CPUs, make sure that this number is factored into the calculator...also, make sure to add in the overclocking numbers (both frequency and vcore voltage).
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a c 134 U Graphics card
a b à CPUs
December 27, 2012 4:04:23 AM

do you think turning off the overclock would help out?
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December 27, 2012 4:16:56 AM

It should (need to emphasis the word should) atleast show if the PSU is struggling...if the GPU usage (not a large amount, just looking for a minor change) go up after the overclock is off, then it would point to the psu not having enough power to run everything. Keep in mind that the 3770k draws about 145 watts stock and 200 overclocked...so it will only theoretically free up 55 watts.
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December 27, 2012 4:47:55 AM

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

This is my power supply.

I really don't know how to underclock my cpu back to factory settings because the CPU overclocked itself automatically on my z77 mobo.
Is there a program that can monitor how much Watt each of the hardware is consuming?

I also dont have much peripherals in my system. Just a mouse/keyboard, SSD, removed the optical drive to save power. Right now, I have 2(7W) fans, 2(9W) fans, and 2(4W) fans on a NZXT fan controller (/w 10w per channel).

Also 1 more thing to note, my cpu never reaches 100% load when gaming. Only during stress test.

Edit:
I checked the clock on core temp, and it decreased from 4.22 to 4.1ghz by itself..(im not sure when)
is this clock fluctuation okay? I have this mobo http://www.newegg.com/Product/Product.aspx?Item=N82E168....
I think this mobo is causing the clock to change... not sure
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December 27, 2012 4:59:51 AM

You probably would need to go into the bios to change the cpu overclock...there should be a default clock option...unless you have a third party software that does the overclocking in the operating system, then you would need to change it in there.

Unfortunately there is not a good program to monitor power consumption....I wish power supplies had a digital read out built into them that showed usage! The easiest way to check power usage would be to use a killawatt plug...problem is that it will only tell you how much power the psu is pulling, it won't tell you how much power the psu is putting out.

I think the easiest way to test your system would be by physically disconnecting one card and then run a game. Then do the same for the second card (to keep the variables to a minimum, please use the cards in their current slot, no need to swap to the first pci port for both cards). Monitor the usage while using a single card, then let us know how they both worked individually.
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December 27, 2012 5:13:09 AM

^ that test refers specifically to the usage of the cards, NOT the system. use the calculator above if you don't believe me.
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Anonymous
a c 117 U Graphics card
a b à CPUs
December 27, 2012 5:15:14 AM

Dude496 said:
^ that test refers specifically to the usage of the cards, NOT the system. use the calculator above if you don't believe me.

how about doing some reading;
Quote:
Power Consumption:
To measure power usage, a Kill A Watt P4400 power meter was used. Note that the numbers represent the power drain for the entire benchmarking system, not just the video cards themselves.
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December 27, 2012 5:21:30 AM

well touche! Everything that I have read (and I guess misread) shows just the 7950 in crossfire using 400 watts.
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December 27, 2012 5:34:19 AM

great!. what about the clock fluctuation? I'm really worried about that. I heard intel chips underclocks itself if it reaches high temperatures to compensate..opposed to AMD chips. I don't know if that is what happened or the mobo just felt like changing the clock w/o my permission..
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Anonymous
a c 117 U Graphics card
a b à CPUs
December 27, 2012 5:46:54 AM

if you only see a 40%-60% cpu usage then it is not throttling unless you didn't install the heatsink.

what are the temps? got this? Core Temp
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December 27, 2012 5:50:27 AM

temps are around 60C-65C at 100% load.
So i guess the mobo is changing the clock speed on its own?

1 more question if I may, I noticed on my OSD that GPU usage are not in sync with each other. GPU1 might be at 70% while GPU2 might be at 30%. Is this normal?
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December 27, 2012 5:51:35 AM

I need to research power usage more...seems that different reviews use different test setups and different methods to test the cards. In the article that loonian provided, they said they tested the cards in a "real world" environment, but did not elaborate. In the below article they elaborated on what they consider stressing the GPU but did not mention the exact program used due to not wanting AMD or NVIDIA to find out and optimize their systems.

http://www.guru3d.com/articles_pages/radeon_hd_7950_cro...

^ that article shows the 7950s using about 280 watts of power by themselves, not including system power...but is that peak power or average power? The article does mention that a 700 watt psu is the minimum recommendation.

So many variables, so many different test setups...rather confusing!
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Anonymous
a c 117 U Graphics card
a b à CPUs
December 27, 2012 6:01:30 AM

Dude496 said:
I need to research power usage more...seems that different reviews use different test setups and different methods to test the cards. In the article that loonian provided, they said they tested the cards in a "real world" environment, but did not elaborate. In the below article they elaborated on what they consider stressing the GPU but did not mention the exact program used due to not wanting AMD or NVIDIA to find out and optimize their systems.

http://www.guru3d.com/articles_pages/radeon_hd_7950_cro...

^ that article shows the 7950s using about 280 watts of power by themselves, not including system power...but is that peak power or average power? The article does mention that a 700 watt psu is the minimum recommendation.

So many variables, so many different test setups...rather confusing!

don't worry about it too much. that article is pretty much spot on.

280 watts for the gpus, 95 watts for a cpu (a sandy bridge i7-3770K stock but it really won't max in gaming) 8 watts for the chipset, 4 watts for each stick of RAM (2) and 5 watts for a hard drive.

thats close to the 402 watts in the power consumption of the other review . .
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January 12, 2014 11:25:10 PM

i would recommend amd for single card uses and nvidia for sli
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