Recurring FPS drops with 6850

NastyN8

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Aug 6, 2012
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Specs:

HIS IceQx Radeon HD 6850 (x2)
AMD Phenom II 1075 X6 @ 3.0 (still using factory settings)
16 GB Gskill RAM 1333
GIGABYTE GA-890GPA-UD3H ATX AMD Motherboard
Ultra LSP750 750-Watt Power Supply
(x2) 500 GB, 7200 RPM HDD in RAID0 array

I was originally running a single 6850 with no problems. I recently decided to go with a Crossfire configuration. After installing the second card, my games looked very good and held a very steady FPS at first, but there was a problem. After about 5-10 minutes of gaming I would start to get FPS drops. My FPS would spike down from 60 to 20-30 and this would become more frequent (at most every 2-3 seconds) if I kept playing which made the gameplay appear choppy. This is happening in GPU intensive games like "Crysis 2" and in fairly non-GPU intensive games like "Orcs Must die". Games are technically "playable" but not enjoyable.

Here is what I have tried so far:

- disable Crossfire - no improvement

- Lowered graphics settings in games - no improvement

- I thought this might be a temperature issue. GPU #1 would reach temperatures of about 85 - 90 (Celsius) on full load and GPU #2 would reach mid 70's at max. I installed another case fan which took the temperatures down by about 3

- Instead of just re-installing drivers, I decided to re-format my HDD and re-install the OS (I like to do this whenever I add new internal hardware)

- removed GPU #2 and went back to my original configuration with GPU #1 only. Removed AMD driver and CAP, Driver sweeper, re-installed driver and CAP. ISSUE PERSISTED !!??!?

- used GPU-Z with only one card and temperature is maxing out at 88 degrees. Still running a bit hot imo.


At this point I am very open to suggestions. It seemed like running the GPUs in Crossfire is what caused my issue so I'm baffled as to why I'm still seeing this problem after completely removing GPU #2. Tonight I am going to try swapping the GPUs to see if one performs better than the other. If that doesn't solve anything, I will start looking at the RAM and PSU. I'm not sure what else to try. Does anyone have any suggestions?



 
Solution
I am thinking it may be heat. Check your case, make sure you have good airflow to the GPU. You may need to get a case fan involved to get cool air immediately available to it. 88 is really pretty hot, I'm running an overclocked 6870 and never get anywhere close to that under load.

One way to verify might be to use CCC's fan control setting and set it to 100%, see if that lets it run longer without the FPS dropping down.

seamus_ar

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Apr 13, 2012
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I am thinking it may be heat. Check your case, make sure you have good airflow to the GPU. You may need to get a case fan involved to get cool air immediately available to it. 88 is really pretty hot, I'm running an overclocked 6870 and never get anywhere close to that under load.

One way to verify might be to use CCC's fan control setting and set it to 100%, see if that lets it run longer without the FPS dropping down.
 
Solution

NastyN8

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Aug 6, 2012
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The motherboard does say its compatible with Crossfire, they should be running at x8 and x8 when using it.

Also, the cards technically "worked" when I was using the crossfire setup - the AMD drivers would detect crossfire and both GPUs would share the load.
 

NastyN8

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I think you may be right. All my slots for case fans are currently used up, so it might even be time to invest in a new/better case. I will try GPU #2 tonight to see if the temps are better with it. If not, I will try to adjust fan speed to 100% like you mentioned.
 

NastyN8

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While we're on the subject... Is it typical to see a wide gap in temps between the two GPUs when running Crossfire?

When I did have Crossfire set up, GPU #2 was running significantly cooler than GPU #1. GPU #1 would reach temperatures of about 85 - 90 (Celsius) on full load and GPU #2 would reach mid 70's at max. Makes me think this whole issue could be caused by a faulty (or maybe even just dusty) heatsink/fan in GPU #1.
 

seamus_ar

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It would certainly be worth your time to clean up the fan and heatsink on the GPU's. On my 6870, I also removed the original heatsink conductive material and replaced it with Arctic Silver 5, which did make several degrees worth of difference under load.

Also if your case has air inlets, make sure they aren't clogged with dust, and also on the video card itself, if it has exhaust vents to blow hot air out of the case, make sure they aren't either clogged with dust or blocked by cables or a wall behind them, allow several inches of clearance for best results.
 

NastyN8

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Thanks for the advice Seamus. I will try this when I get home tonight. I've never had to open up a GPU before, but I just watched some vids on re-applying the thermal compound on a GPU and it seems fairly easy to do. I will let you know what happens.
 

jerseygamer

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Your problem is a common driver issue. Its been around for over a year. It comes and goes. 12.4 required alot of 6000 users to have to disable crossfire and re-enable it every time they booted up to avoid it. 12.6 official release causes this problem ALL of the time at random for 6000 users in some cases. Basicly go back to the 12.4 drivers and re-enable xfire every time you boot up and wait for a fix.
 

NastyN8

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I should still probably address the GPU temperature issue whether or not this driver problem is the root cause of my problem or not. So I will start by doing that. However, if the AMD drivers do have an issue like this it would definitely be worth looking into.

Is there an AMD post or another forum post that goes into this driver issue in detail?

Is this something that you would only see with Crossfire? I still have the same problem with only 1 GPU installed.

By re-enabling crossfire, do you mean just going into the CCC and disable, apply settings, enable, apply settings? Or would I have to start my computer with Crossfire disabled and then enable?
 

seamus_ar

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Just a note on removing the cooler from a video card: some are quite simple; my Asus 6870 has only four screws. However, I've seen some with many many screws...my old 4870 comes to mind.

A pill bottle or a piece of duct tape to hold screws can go a long way towards helping avoid frustration. Also if it looks like a complicated setup, grab your digital camera and take pictures. Pics can help a great deal when you are trying to remember if the green wire or the black wire on this connector was on top...
 

NastyN8

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I fixed my issue!

You were right seamus, it was a temperature issue. However, it was my CPU, not my GPUs.

I bought some thermal compound, applied it, and cleaned my heatsink on the GPU. It did not fix my issue, but my GPU ran about 20 degrees cooler after that!

I then started monitoring my computer components very carefully as I was gaming and I noticed that my issue started when my CPU reached a certain temperature. I inspected the radiator on my H60 and I couldn't believe how much dust was on it!

I then cleaned out the radiator and applied new thermal compound to the CPU. My CPU started to run much cooler and my issue became non existent! I even got my Crossfire up and running with the latest AMD drivers and no issues (so far).

Gaming looks great now!