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Old Jan 2, 2013, 09:12 PM   #451
janbuyse
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In my experience, these chips are made with some headroom in terms of clocks and temperature. So while you should be carefull as to how high you try to overclock your hardware, but doing so won't likely break anything.
Concerning the limits, you should know that every single chip is different in quality, thus making it impossible to state exact limits. One may get +200MHz, another one may get even more. The important part is to find out your sweetspot by increasint in small steps (20MHz, e.g.) Then you have to consider temperatures. I, personally, wouldn't go above 100C. +200MHz GPU and +300MHz Memory got me spikes of 84C after 3 houres of FarCry 3, which are roughly the same temperatures I had without OC. This tells me that I have got some headroom left and I do not worry.
I hope my post helped!
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Old Jan 2, 2013, 09:25 PM   #452
loki101
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Quote:
Originally Posted by janbuyse View Post
In my experience, these chips are made with some headroom in terms of clocks and temperature. So while you should be carefull as to how high you try to overclock your hardware, but doing so won't likely break anything.
Concerning the limits, you should know that every single chip is different in quality, thus making it impossible to state exact limits. One may get +200MHz, another one may get even more. The important part is to find out your sweetspot by increasint in small steps (20MHz, e.g.) Then you have to consider temperatures. I, personally, wouldn't go above 100C. +200MHz GPU and +300MHz Memory got me spikes of 84C after 3 houres of FarCry 3, which are roughly the same temperatures I had without OC. This tells me that I have got some headroom left and I do not worry.
I hope my post helped!
That's great, thanks janbuyse. So essentially, to find the 'sweet spot', I just need to to incrementally push the card till I get performance gains with little to no difference in temperature? I'm assuming the best way to test the sweet spot is through pushing the card with a game like Far Cry 3? Or is there something built into the overclocking software that I can click on and it can tell me "Keep those settings if you want to set your house on fire." etc?
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Old Jan 3, 2013, 03:24 AM   #453
janbuyse
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Exactly, you should try it with demanding games like FarCry 3. In my experience, Futuremark performance tests rarely make the GPU go above 80C, 4 Degrees shy of what FarCry 3 does to my system.
You should also pay attention to screen quality while playing. If you start to notice any form of artefacts that are completely uncommon to the game (FarCry 3, for example, has some texture issues sometimes, but these appear regardless of OC'ing and are game related), you are pushing the card a bit too far.
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Old Jan 3, 2013, 05:26 AM   #454
loki101
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Great, I look forward to giving it a go... If my iMac ever arrives! Any recommendation for overclocking software? I've looked around and will probably go with EVGA or MSI's offering.
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Old Jan 3, 2013, 08:48 AM   #455
janbuyse
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When did you order your iMac? I use the EVGA tool, which works fine for me.
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Old Jan 3, 2013, 09:36 AM   #456
loki101
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I ordered on the 2nd Nov. Apparently it has arrived in London, still not sure when to expect it though.
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Old Jan 3, 2013, 02:23 PM   #457
janbuyse
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I hope soon, the thing is a beauty!
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Old Jan 3, 2013, 09:40 PM   #458
ddarko
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Originally Posted by loki101 View Post
Hey guys, I've been keeping an eye on this thread for weeks, still awaiting the delivery of my iMac... But thanks to all your posts I can't wait till it arrives!

Anyway, I had a couple of questions. 1. Will overclocking likely cause damage to an iMac? 2. If an iMac 'died' while being overclocked would it still be covered by Applecare? (Or, would Apple be able to tell you had overclocked it?)
Quote:
Originally Posted by janbuyse View Post
In my experience, these chips are made with some headroom in terms of clocks and temperature.
My personal opinion is that overclocking in an all-in-one enclosure is a risky idea and you should avoid it. The heat tolerances are much tighter in an iMac than in a standard desktop case. The general rules of thumbs that apply to overclocking a PC add-in card in a relatively open and ventilated desktop case cannot be carried over to overclocking a GPU in the tight spaces of an iMac. There's a reason why Nvidia underclocked the 680MX in the iMac in comparison to the 680 used in desktop add-in cards - heat!

I'm not saying that no one has ever overclocked their iMac successfully but the tolerances are much less forgiving in an iMac than they are in a regular desktop case. It is not just a matter of whether or not the 680MX has the headroom to overclock - with an all-in-one case, you have to also consider the heat you are adding to the entire system and the impact the additional heat generated by the GPU overclock may have on the other system components that are closely packed together in an iMac. One user earlier in the thread measured the overclocked GPU temp at 89-90 degrees celsius but what was the temp within the case? I can guarantee you the ambient air temperature within the iMac rose significantly with the GPU overclocked. What's the effect of the increased environmental temperature on the memory, the hard drive and the CPU, all components that have their own heat tolerances?

Overclocking the GPU also likely voids your warranty. Apple's UK iMac warranty says in part:

Quote:
This warranty does not apply: (a) [edit]; (b) [edit]; (c) [edit]; (d) [edit]; (e) to damage caused by operating the Apple Product outside Apple’s published guidelines; (f) [edit]; (g) to an Apple Product that has been modified to alter functionality or capability without the written permission of Apple
It's very possible if you run into trouble and you bring it to Apple, they will service it anyway, but if they want to be stickler about it, they could say GPU overclocking fell under (e) and (g) and damage caused by it isn't covered. And yes, Apple would be able to tell that you were overclocking the card.

It is your choice but overclocking your new iMac has both technical and legal risks. I say enjoy your new iMac as it is!

Last edited by ddarko; Jan 3, 2013 at 10:18 PM.
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Old Jan 3, 2013, 10:37 PM   #459
elithrar
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Originally Posted by ddarko View Post
It's very possible if you run into trouble and you bring it to Apple, they will service it anyway, but if they want to be stickler about it, they could say GPU overclocking fell under (e) and (g) and damage caused by it isn't covered. And yes, Apple would be able to tell that you were overclocking the card.

It is your choice but overclocking your new iMac has both technical and legal risks. I say enjoy your new iMac as it is!
Software overclocking would only be obvious if they 1) booted into Windows and 2) checked the clock speeds after doing so.

When in Mac OS X, it's unlikely they'll know (as the card will default to stock speeds), and as Windows itself is "unsupported" there's little reason for them to waste time digging around your Windows installation when trying to fix a problem.

(note that this does not mean you shouldn't be careful when overclocking. Baby steps, and keep tabs on heat/artifacts when starting out)

----------

Quote:
Originally Posted by maxira View Post
any type of OC decreases the life of all the electronic components
Not always (esp. if it's still operating within normal parameters).

Further, the decrease in lifespan is likely to be small and with hardware life likely to be 5-6+ years for a non-dud part, a few months off the end isn't likely to cause you any problems. If you're the kind of person to overclock your hardware, chances are you will have moved on to a new machine by that stage.
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Old Jan 4, 2013, 10:04 AM   #460
swarleystinson
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Quote:
Originally Posted by ddarko View Post
My personal opinion is that overclocking in an all-in-one enclosure is a risky idea and you should avoid it. The heat tolerances are much tighter in an iMac than in a standard desktop case. The general rules of thumbs that apply to overclocking a PC add-in card in a relatively open and ventilated desktop case cannot be carried over to overclocking a GPU in the tight spaces of an iMac. There's a reason why Nvidia underclocked the 680MX in the iMac in comparison to the 680 used in desktop add-in cards - heat! ...
I'm not saying that no one has ever overclocked their iMac successfully but
First, some background.
I've owned and successfully overclocked the 2010 iMac making many games play a solid a 60 fps that otherwise wouldn't. I then sold that after a year and bought a top-of-the-line 2011 iMac and did the same thing. (I have a thread about it on these forums). Neither time did I ever experience any problems and I would play sometimes for 8 hrs straight when I had free time when the wife was out of town. As the poster before mentioned, you just have to be careful. It may indeed void your warranty, though knowing apple, I'm sure as long as you're not messing with hardware itself, they probably would fix it anyways. But I would buy the AppleCare protection just in case. Many many PC overclockers scoff at the notion of being able to overclock an iMac, but they're wrong. While you may not be able to get dramatic gains like in a thoroughly cooled PC, an iMac can absolutely be safely overclocked assuming the following:

1) You're just overclocking the GPU. Don't try a CPU and a GPU overclock. Although it may be possible, I've never attempted it and so can't speak to its safety. As this guy said, ambient temperature could certainly affect other components.

2) You don't attempt to mess with the voltage at all. Most desktop overclocking software lets you apply more voltage to the chip -- this would be HIGHLY RISKY in an iMac, where voltage requirements are considered very carefully by the engineers and usually the power supply unit (which determines the amount of juice the entire machine will draw from your wall outlet) usually takes just enough power to supply all the components under full load.

3) You mind your temps!

4) You mind your expectations! Don't expect crazy overclock numbers. We're talking a couple of hundred MHz on your memory clocks, and probably only a hundred MHz on your core clocks if the past 2 generations of ATI Radeon iMacs are any indication. That's probably it.

5) Go slow! As the prior poster said, only go up 20-50 MHz at a time. And start with memory clocks as these tend to have less of an effect on temperature than core clocks.

Just crank up the fans before you do the testing, and err on the side of cooler temps. There is GPU overclock headroom because there is cooling headroom! Usually, mac fans seem to come on much later after the temps have really started spiking, which leads me to believe that either A) the engineers are stupid or B) the mac is designed to allow higher operating temperatures than in a typical desktop environment (in the 90C degree range). So you're not going to be seeing temps in the 30-40C range like in a custom built gaming rig. I personally don't like seeing my temps hit 90C under any circumstances - in fact, usually my temps on the previous iMacs were in the 60s and 70s. So I would err on safety first, especially if you plan on extended gaming sessions -- I find, e.g., "just one more game" on Black Ops 2 is never that. A fan is a lot cheaper to replace than a mobile GPU!!!

Get SMC fan control for bootcamp/windows, it's a simple app let's you crank up the fan speeds ... it just requires some basic ms-dos knowledge. I usually crank up the fans to near max.

E.g., on the mid-2011 iMac, max fan speeds are 2600, 5000, and 2600 rpm, respectively. I would set the fans to 2500, 4500, and 2500 rpm.
I downloaded SMC fan control (the .exe file is called macfanx64.exe). I would unzip the download and rename the folder 'macfan' and place it in the desktop. Then, I would enter the dos command window through the start menu. Type in cd\{insert name of where you put folder}. (e.g., cd\users\YOUR WINDOWS NAME\desktop\macfan. Then type macfanx64 2500 4500 2500. Then I would proceed to get my overclock on with Sapphire Trixx.

Haven't yet gotten my 2012, but I'll be sure to start a new OC'ing thread once I do! If you'd rather wait a month or so for that thread, then be my guest, otherwise, feel free to play, and please share you experience if you do!

If you have any additional questions about overclocking, just google 'GPU overclocking guide'. You'll find ample resources. Read a few and learn as you go. And have fun tinkering!
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Old Jan 4, 2013, 12:16 PM   #461
ddarko
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Quote:
Originally Posted by swarleystinson View Post
First, some background.
I've owned and successfully overclocked the 2010 iMac making many games play a solid a 60 fps that otherwise wouldn't. I then sold that after a year and bought a top-of-the-line 2011 iMac and did the same thing. (I have a thread about it on these forums). Neither time did I ever experience any problems
The uncertainty is that it's a new case design with a new layout, new mobo design and new components. Not to dismiss the value of your past overclocking success but I'd be cautious about assuming because you overclocked iMac models in the past, you will be able to do so in the future. Maybe or maybe not. Lots of variables have changed with the new iMac and the past is not necessarily a reliable predictor of the future.

Quote:
It may indeed void your warranty, though knowing apple, I'm sure as long as you're not messing with hardware itself, they probably would fix it anyways. But I would buy the AppleCare protection just in case.
Buying AppleCare isn't a solution - AppleCare extends the 1-year hardware warranty for an addition two years but it doesn't expand the scope of the warranty. Overclocking isn't covered any more under AppleCare than it is with the out-of-box warranty.

The overclocking advice you give is sound but I think the poster who asked about it should carefully weigh the risks as well. The biggest to me is that it does void the warranty and you will be giving up the legal protections afforded by the warranty and be at the mercy of Apple's good will for repairs if anything goes wrong. Everyone's tolerance for risk is different and I guess mine would be pretty low for a new $2800 iMac.
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Old Jan 4, 2013, 12:30 PM   #462
loki101
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Thanks guys! swarleystinson, for your detailed additional guidance and advice, ddarko, for your words of warning. I will weight my options carefully and see how I get on... When the machine arrives... on Monday... Potentially...
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Old Jan 4, 2013, 05:52 PM   #463
swarleystinson
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Quote:
Originally Posted by ddarko View Post
The uncertainty is that it's a new case design with a new layout, new mobo design and new components. Not to dismiss the value of your past overclocking success but I'd be cautious about assuming because you overclocked iMac models in the past, you will be able to do so in the future. Maybe or maybe not. Lots of variables have changed with the new iMac and the past is not necessarily a reliable predictor of the future.

Buying AppleCare isn't a solution - AppleCare extends the 1-year hardware warranty for an addition two years but it doesn't expand the scope of the warranty. Overclocking isn't covered any more under AppleCare than it is with the out-of-box warranty.
Both excellent points. Looking at the teardown pics it does appear the new iMac's innards are slightly more concentrated. Having read several reports though, it does seem that it cools fairly well.

As I said, I'll be sure to post a thread when I receive mine. I'll be ordering it tomorrow
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Old Jan 5, 2013, 09:29 AM   #464
Haugiz
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New drivers out today, 310.90: http://www.geforce.com/drivers/results/55125

Seems like Far Cry 3 is getting a boost...

edit: linked to the desktop version - fixed now

Last edited by Haugiz; Jan 5, 2013 at 10:03 AM.
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Old Jan 5, 2013, 10:06 AM   #465
AndiS.
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Originally Posted by Haugiz View Post
New drivers out today, 310.90: http://www.geforce.com/drivers/results/55125

Seems like Far Cry 3 is getting a boost...

edit: linked to the desktop version - fixed now
thanks for the heads up, have you tried the drivers yet?
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Old Jan 5, 2013, 10:15 AM   #466
Trinite
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Originally Posted by Haugiz View Post
New drivers out today, 310.90: http://www.geforce.com/drivers/results/55125

Seems like Far Cry 3 is getting a boost...

edit: linked to the desktop version - fixed now

Doesn't seem to say it's for the 680MX, just 680M. Is that a problem?
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Old Jan 5, 2013, 10:24 AM   #467
AndiS.
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Doesn't seem to say it's for the 680MX, just 680M. Is that a problem?
they work, but I hope there will be drivers soon, which support the 680MX officially.
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Old Jan 5, 2013, 10:46 AM   #468
loki101
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Originally Posted by Haugiz View Post
New drivers out today, 310.90: http://www.geforce.com/drivers/results/55125

Seems like Far Cry 3 is getting a boost...

edit: linked to the desktop version - fixed now
The upto 38% boost outlined in the description seems to be a feature of the R310 Driver family, so the boost is the same as the previous driver released in December... I think.
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Old Jan 5, 2013, 12:46 PM   #469
swarleystinson
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The upto 38% boost outlined in the description seems to be a feature of the R310 Driver family, so the boost is the same as the previous driver released in December... I think.
So then we shouldn't expect any better benchmarks than what people posted here in this thread for FC3?

Also, if it supports 680m it will very likely support 680mx as well ... it's just mx is only in iMacs, so they may not release it on their release notes.
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Old Jan 5, 2013, 01:13 PM   #470
loki101
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Originally Posted by swarleystinson View Post
So then we shouldn't expect any better benchmarks than what people posted here in this thread for FC3?

Also, if it supports 680m it will very likely support 680mx as well ... it's just mx is only in iMacs, so they may not release it on their release notes.
Yeah, I don't think there will be a difference in performance, there might be, but looking at the notes I don't think so. There was definitely a difference with the original R310 driver though.!
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Old Jan 5, 2013, 02:38 PM   #471
AndiS.
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Yeah, I don't think there will be a difference in performance, there might be, but looking at the notes I don't think so. There was definitely a difference with the original R310 driver though.!
haven't noticed a difference so far, runs as well as before
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Old Jan 5, 2013, 04:14 PM   #472
swarleystinson
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What I've noticed in general with the past two iterations (both overclocked):

Mid-2010: You could NOT play the more demanding games like Crysis 1/2, Metro 2033 at native resolution. Newer and still somewhat demanding: native res only with major cuts to options (most things low/medium). Almost no new game could do native +AA. Newer and less demanding (e.g., CoD MW) and older games such as HL2 could run excellent.

Mid-2011: The crysis and metro games still ran poorly on native res but were playable if you messed with the settings. DX11 was available, but made almost every game unplayable. Middle-of-the-road newer could played at native res with some tinkering. Newer less demanding games (CoD etc) could be played with 2x-4x AA at native res otherwise max spec.
Older games and valve games such as HL2, portal1/2 pretty max spec.

It seems like 2012 will run pretty much everything you throw at it in the 1900x1080 range with all the settings on high (e.g., FC3). The newer games are now playable at max spec, but you have do some tinkering.

----------

... that said,

Would anybody mind giving us a Metro 2033 Benchmark running at 1900x1080? (Pretty please )
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Old Jan 6, 2013, 02:41 AM   #473
Haugiz
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Originally Posted by swarleystinson View Post

Would anybody mind giving us a Metro 2033 Benchmark running at 1900x1080? (Pretty please )
I'm downloading it now via steam now - the game was free for a couple of days before christmas. It seems to be a benchmark tool included in a dlc. I'll give it a go a little later when the download finishes.
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Old Jan 6, 2013, 03:20 AM   #474
Grockel
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Please excuse me asking a basic question, as I'm still waiting for my first Mac.

Have I understood correctly that:

(i) Drivers provided by NVidia are Windows drivers, only relevant if you are using Windows in some manner (e.g. Bootcamp); and

(ii) OSX drivers for the 680MX would come via Apple ?
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Old Jan 6, 2013, 05:55 AM   #475
TweakOnline
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What should I do?
I love Apple, and I love Battlefield 3.

I got a Intel i7 920, Nvidia 470GTX, 16GB of ram and 2TB + 128GB SSD of storage. I want to buy an Apple iMac, but I'm not sure if I could run Battlefield 4 (all settings max, 1920x1080) in the future too; Did anyone tested the beta of Crysis 3 yet? Those games do really need powerhouses, and before I'm going to buy an iMac I really need to know if it can run smoothly on a 680MX GPU...

What do you think guys?
Spending 3000 bucks or skip the iMac and buy a *ugly* *big* *plastic* *with 1920x1080 lcd* powerhouse? hehe
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