This is a Public Service Announcement to inform the Mac and PC users of what appears to be a fundamental change in client behaviour regarding the maxFPS and maxFPSbk settings.
In previous versions of the client, if your video card just couldn't muster that juicy 60 FPS no matter what, having the FPS limiter (maxFPS; maxFPSbk) turned off (set to zero) would at least let you eek out as much as you could from your card. The GPU wouldn't run at 100% because it was behaving properly (idling) when it couldn't do anything in a given cycle.
The 5.0.4 client appears to have changed how this works. In 5.0.4 it appears that if you do not cap your FPS, usually to your display's maximum refresh rate, the GPU will no longer idle, but continue working at full load even though it isn't producing any higher framerates.
This has a very detrimental effect: heat.
You see, when a CPU or GPU is incapable of performing any additional action/rendering beyond what it can pull in any given environment, it usually idles to save power. In WoW's case, being that the game client is more CPU bound than GPU bound, that means your FPS is typically primarily dictated by your CPU's core speed and bus speed (and sometimes RAM speed). The more modern the CPU and/or faster it is, the higher your framerate gets.
But now it seems that the Mac client (and possibly PC client too) are somehow causing the GPU to never idle if the FPS is not capped. Here's an example from my system:
I have a Mac Pro 1,1, which has two 2.66 GHz Xeon 5150 CPUs, each with two cores. In the Cataclysm client (4.x), I had my FPS limiter set to zero because other than the old Azeroth zones, I didn't get much more than about 40-45 FPS because my CPU wasn't ultra fast and didn't have a modern bus architecture. I didn't need to limit my FPS because it never got uber high except in a cave or house, or a few dungeons (and certainly never in raids). So I had the FPS limiter turned off and VSync turned on (to prevent tearing).
Fast forward to 5.0.4's launch. My framerates didn't change, nor did any of my settings. My FPS was still not limited and VSync was still enabled. However, I noticed that my Mac Pro's chassis got remarkably hot to the touch around the PCI Expansion Bay. So I opened Hardware Monitor and saw something that shouldn't have been: GPU Load - 100%. It was 100% at the login screen. It was 100% at the character select screen. It was even 100% around Dalaran, where I usually get only 20-30 FPS tops no matter what. And I was still getting only 20-30 FPS there.
So I went through my config.wtf file's settings and one by one eliminated the settings lines after each launch until I found what was causing my GPU to cook itself. Even though my framerates didn't change (because my settings didn't change), the GPU was now heating up in short order. All that changed was how the GPU operated when the WoW client was open. It no longer had any idle cycles. With the FPS limiter turned off, the client was telling the GPU to run as fast as possible, even if it didn't produce more frames per second, and what that amounted to was nothing but extra heat being generated. A lot of heat.
So why am I explaining all of this to you here? So you can prevent the untimely demise of your computer's video card/GPU.
So the old client let your graphics card processor idle when there wasn't enough data to feed to it (i.e. couldn't muster high framerates because of the CPU bottleneck). This client does not do so, and in turn, if you fail to limit your FPS, you could very well cook your computer into an early grave.
So the moral of the story is that as of this client version, under no circumstances should you leave your FPS uncapped. It should be set at the most to your display's maximum refresh rate. Doing so causes the client to allow your GPU to idle when it isn't actively receiving data through the bus instead of burning itself out.
To limit your framerate, you can do one of two things:
In the game, from either the login screen or the in-game world do the following:
From the Login Screen:
1) Click the System button.
2) Click the Advanced menu option.
3) Tick the checkboxes for both the Max Foreground FPS and Max Background FPS options.
4) Adjust the slider to your desired position. For LCD owners, this would be putting the slider marker directly under the letter o in the word Background and directly underneath the second o in the word Foreground. Both markers should align with each other if you want as close to 60 FPS as possible using just the sliders.
From the in-game ESC menu
Follow the instructions as listed above for the Login Screen (the buttons are all the same).
Open your config.wtf file, located in the /World of Warcraft/WTF/ folder and make sure the following lines are present:
SET maxFPS "60"
SET maxFPSbk "60"
You can (and should) adjust these to lower values if your video card cannot normally handle that high of a framerate naturally.
For laptops and some lesser powered iMacs, it is advisable not to exceed a value of 30 for either of these settings unless you have absolutely awesome cooling available for your computer.
So to recap, as of 5.0.4 failure to limit your framerates will cause your graphics card to never idle, potentially causing it to overheat and/or burn out.
Play it safe and cap your FPS!
The following is an addendum post created by Perma to also help with overheating in his computer, but that could very well help a lot of the players here, so I am adding it to this sticky:
Cleaned my mac's exhaust vents with a $10 can of air
+15 - 25 FPS
-20C of CPU temperature
Increased visual settings
Disclaimer: If your computer is still under Applecare, or you don't feel comfortable taking apart your computer, take it into the store to get it cleaned. Opening your computer, or spraying air in the back, may void your Applecare / warrantee.
I have an older 2008 MBP(10.6.6, 2.5ghz, 4gb RAM, 512MB 8600 GT M) that has been running awfully since mop, we're talking 18fps during combat on the lowest settings, with the lowest resolution, with a processor at 80C. I was having input lag, and my computer was hotter than the inside of a hot pocket straight from the microwave.
After combing through the internets, I found the culprit. DUST.
I am not a smoker, and I take good care of my mac. This dust is just acquired rom regular use.
According to this video, (http://www.youtube.com/watch?v=Ts33ujKlG2k) there are heat fins along the back of the computer, similar to a car radiator. They're spaced really close together, so it's really easy for them to clog up with dust. Clogged fins = reduced heat loss = reduced performance = reduced happiness.
I cleaned out the back vents today with an air duster, and what an improvement. Now, blowing air into the vents through the back is not the best way to clean the laptop out, but I didn't have a torx screw driver to open the case.
For best results, you should open up the case and clean out the whole computer. There are lots of good instructions on how to do it on www.ifixit.com, or if you don't feel comfortable doing it, take it to an Apple Store.
Currently, I've been sitting in The Shrine of Two Moons for 15 mins, my FPS is capped at 35FPS with Good settings, and my processor is between 55-65C. This is a huge improvement for someone who's been playing on the lowest settings since WotLK.
I bought the can of air from my local big box store for $10, I'm sure you could get it cheaper elsewhere.
Make sure you follow the directions on the can of air for best use practices. Don't turn it on it's side or upside down. Use the straw that comes with it.
I also added the little rubber bumpers that you would use on a cabinet door to the bottom of the case, to add some additional airflow. You can get them from the dollar store, and they remove easily.
Another performance tip is to set your background FPS to the lowest, which is 8 fps. There's no point in having the game work hard when you're not even looking at it.
Hopefully this helps some people enjoy MOP a little more.
Edit: Added notation that this is also for PC users.
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