Is my cpu bottlenecking my HD 7950?

[nociception]

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)

 

[hapkido]

If your CPU usage is 60%, it's not causing a bottleneck. Have you installed the latest crossfire profiles?

 

[Guest]

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.

 

[ikaz]

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 ?

 

[nociception]

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).

 

[bigshootr8]

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_V2GymyCWM2oTYTeg&index=5

 

[nociception]

okay. Great!
But for future references, can anyone tell me if this GPU usage fluctuations are normal?

 

[nociception]

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:

 

[Guest]

i highly doubt 3gbs of Vram was needed to run 1920x1080

 

[bigshootr8]

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.

 

[Dude496]

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.

 

[nociception]

its a seasonic 750w 80 plus gold.

 

[nociception]

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?

 

[Dude496]

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.

 

[bigshootr8]

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.

 

[Dude496]

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.

 

[bigshootr8]

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

 

[Dude496]

its a seasonic 750w 80 plus gold.

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.

 

[bigshootr8]

Oh, yea my apologies reading a few posts yea a 700 watt would be a good range normally though you would end up in the 750 range like a tx750
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021

 

[Dude496]

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-overclocking-core-i7-3770k,3198-11.html

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).

 

[bigshootr8]

do you think turning off the overclock would help out?

 

[Dude496]

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.

 

[nociception]

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151087

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=N82E16813131837.
I think this mobo is causing the clock to change... not sure

 

[Dude496]

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.

 

[Guest]

your PSU is fine:
AMD Radeon HD 7950 CrossFire & TriFire Review

i doubt the "test system" was an i3 . . . :lol: