8350 OC Bottlenecking GTX 660 SLI

istari675 · May 23, 2014

I just got a second card installed but when I try to game with it I always hit a CPU bottleneck. I haven't been able to get both of the cards very far past about 50% usage, which is quite ironically frustrating. In BF4 the cards stay about 40-50% usage, while the CPU is at around 50% useage and the FPS is very jagged around 30-50. Similar performance shows up in all graphics demanding games I have checked with as well.

FX-8350 4.7 clock 1.35v
ASUS GTX 660 DCUII OC SLI
Sabertooth 990FX R2.0
Rosewill Hive 650W

Onus · May 23, 2014

With your CPU not at 100%, there may be another bottleneck, and I suspect it is the platform. OC your NB. This thought is based on some old data; hopefully someone with more current metrics can step in on this, but I don't think it is the CPU.

istari675 · May 23, 2014

Onus :

I currently have a water cooling system on my CPU (H80i) and just have a 92mm fan aimed at the vcore. Would overclocking the NB cause a temp concern?

Onus · May 23, 2014

On a Sabertooth? Probably not, but you always watch your temps when overclocking, and take it in small steps.

lowriderflow · May 23, 2014

sounds like you have alot connected to that power supply... 650 is hte minimum for SLI. but those dont take account overclocks.

i'm not sure it's enough for a power hungry 8350... and i'm going to guess you have your GPUs overclocked as well?

try resetting everything to stock speeds, and see if you actually 'get more with less'.

then you know you'll need a bigger PSU

Onus · May 23, 2014

That could be, but the Hive is a decent PSU, and the GTX660 is a pretty frugal card, with only one 6-pin PCIe power connector, so 650W ought to be enough.

maddogfargo · May 23, 2014

8350 @ 4.7 with LLC voltage bump under load will pull a LOT of current. Make sure you have a good PSU.

It will also generate a LOT of heat. An H80i should be able to handle it, provided your case has good ventilation and you aren't getting heat build up from the SLI setup.

BF4 will use the cores the 8350 has available. What CPU usage are you seeing while gaming?

I've had a Phenom II x6 1090T @ 4.0GHz able to drive 2 HD 7950's to 95-99% usage in crossfire playing Crysis 3. So the platform is capable of good performance when tuned properly.

For SLI, you NEED to have a 990FX board. If you are on a 970 board the chipset will not support both cards at x16. A 990FX board will do both GPUs at x16. This may be your problem.

Hope this info helped.

Onus · May 23, 2014

The Sabertooth is a 990FX. Make sure the two cards are in x16 slots.

maddogfargo · May 23, 2014

Onus :

Yup, I just missed that detail above. Board should be fine, checking the slots being used is a good call.

istari675 · May 23, 2014

maddogfargo :

The temps haven't increased since installing the second 660. While gaming all cores go to around 30-50% and never see any spikes going anywhere past that area, even though there are serious stutters in game. I could use some help on which slot is x16 since I just put the card in the slot that seemed to make sense. It was the same color as the first cards slot. Also if I were to try and put it in any of the other slots the fans on the card wouldn't have room for the air to flow.

Onus :

Tried that out and I didn't see any improvement at all.

Onus · May 23, 2014

You want to use the two tan slots; the one nearest the CPU, and the one that is the same color.

istari675 · May 23, 2014

Onus :

That is the one I slotted it into. I did notice though that one of the cards is labeled "PCI-E 3.0 x 16 @ x8 2.0" using NVIDIA Inspector.

plaintuts · May 23, 2014

lower your cpu OC to 4.4 then check for improvements.

if the fps normalizes in games then, you may need to up the voltage on your 4.7 OC for stability.

istari675 · May 23, 2014

plaintuts :

Tried it with no improvement.

plaintuts · May 23, 2014

thats odd then,

i have an sli of gtx760 on my 8350, its not showing signs of bottleneck..

have you tried bios update? driver update? every update?

istari675 · May 23, 2014

plaintuts :

BIOS, windows updates, video card drivers + bios, audio drivers, I got everything that comes to mind updated in the last week.

plaintuts · May 23, 2014

swapping the gpu posistion?

but basically, since your gpu or cpu are not hitting at least 80% on games then the problem maybe somewhere else.

can you reset all your OC back to defaults, CPU and GPU then check if the problem worsens.

istari675 · May 23, 2014

plaintuts :

I tried that when you said to set the CPU to the default clock. Got everything to its stock settings and lost a good 10 FPS. I got my CPU and both GPUs to hit 99% usage through using 2 different stability testing softwares so I don't think it has anything to do with the PSU at this point either.

plaintuts · May 23, 2014

this may sound tedious,

remove your SLI config

one at a time, heaven benchmark your gpu on stock cpu clock,

just to check if a marginal difference will occur.

if nothing, then

unless this is a driver issue, an overclock instability or ram overclock,

the sabertooth is a good mobo but 30 fps on an OC'd SLI, somethings wrong.

Onus · May 23, 2014

Testing the cards individually does seem to be a reasonable thing to do to rule out a card problem.

coolcole01 · May 23, 2014

Run the valley 1.0 bench in sli in full screen and post the scores.

istari675 · May 23, 2014

Onus :

In Heaven Benchmark:
SLI - 1827
Card A - 1066
Card B - 1062

They stick very close to 99% usage using heaven. A single bad card doesn't seem to be the issue.

coolcole01 · May 23, 2014

If you are getting 99% usage the cpu is definitely not a problem

coolcole01 · May 23, 2014

If that's at 1080 at extreme hd 1800 is pretty good

istari675 · May 23, 2014

coolcole01 :

Full screen max settings on Unigine Valley Benchmark got:

FPS: 52.8
Score: 2209
Min FPS: 20.3
Max FPS: 66.8

Benchmarking programs like that have no problem pushing the SLI to its limits. Its just when I play a game with the setup I don't see CPU usage, GPU usage, or FPS maxed out. Also the last benchmark was just to compare the two cards so I didn't have it running at 1920x1080.

8350 OC Bottlenecking GTX 660 SLI

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