Results of 2011 iMac Overclock (bootcamp, prelim)

[SnorLars]

Hey swarleystinson
Thanks alot for this.

I'm a first time OC:er and tried OC at stock voltage (i.e. 710/1000). However that ain't giving me any increase at all in the game I'm playing (IL-2 Sturmovik: Cliffs of Dover).
Noticed that the card is fairly cool when cranking up the fans so would like to try your OC.
But what voltage did you go for and could you briefly describe the process?

I know I should up the core clock first in increments, then the mem clock but dunno how to work the voltage.

Btw, what drivers are you on?


I tried ATT first but it locked the comp. Then MSI Afterburner but the new clocks wouldn't stick in game.
I use ATT for monitoring in game.

Nevermind. I tried 800/1100 with TRIXX and not much to it. Didn't have to touch the voltage apparently. Gave me 3 more frames in average and a tad more smoothness which is very much welcomed.

Kewl thing with ATI Tray Tools is that u can see the temps and speeds and whatever in the game using OSD. Can't find that option in GPU-Z.

EDIT: Noticed ATI Tray Tools take chunk of your fps so now after thoroughly watching the temps through many hours of gaming I've shut it down.

 

[A Macbook Pro]

Fan control keeps crashing on startup for me. Is there an alternative? I see TRIXX has fan control but it works on a percentage system not on those 3 sets of numbers like you mentioned. I changed the core and memory clock in TRIXX like you said to and it increased my frame-rate in intensive games by 5fps which is exactly what I was hoping for. I keep the fans up and the temperatures don't get too high. Very happy with this.

 

[SnorLars]

Fan control keeps crashing on startup for me. Is there an alternative? I see TRIXX has fan control but it works on a percentage system not on those 3 sets of numbers like you mentioned. I changed the core and memory clock in TRIXX like you said to and it increased my frame-rate in intensive games by 5fps which is exactly what I was hoping for. I keep the fans up and the temperatures don't get too high. Very happy with this.

I use smcfancontrol to speed up the three fans (ODD/HDD/CPU), then reboot into W7 where I tell TRIXX to run the GPU fan on 100%. You have to run smcfancontrol from mac osx and reboot. The fanspeeds will stick through the reboot.
Keeps everything cool but the noise is really too high without headphones.
The comp is in the livingroom so the wife has forced me to lower the speeds.

I get temps close to 90 degrees but from what I've read this is ok for an iMac.
If I game without overclocking the temps get close to 90 too.

 

[A Macbook Pro]

I use smcfancontrol to speed up the three fans (ODD/HDD/CPU), then reboot into W7 where I tell TRIXX to run the GPU fan on 100%. You have to run smcfancontrol from mac osx and reboot. The fanspeeds will stick through the reboot.
Keeps everything cool but the noise is really too high without headphones.
The comp is in the livingroom so the wife has forced me to lower the speeds.

I get temps close to 90 degrees but from what I've read this is ok for an iMac.
If I game without overclocking the temps get close to 90 too.

For me I'm rarely hitting over 80 degrees and that's when really pushing a game that doesn't want to give me over 35 FPS at max settings. I think that's pretty decent, but I'll let Battlefield 3 be the judge of that

 

[Kerel]

I got my base 21" 2011 Imac up from 600/800 to 800/1000 with TriXX.
Im not using any fanspeed control and temps stay under 80c.

Shader speed is maxed out with trixx and i tried 1050 for the memory but it was unstable.

Found out that the memory is rated for 2 different settings:
1.25Ghz @ 1.5 volts and
800Mhz @ 1.35 volts
So if the memory of my HD6750m runs at 1.35v im pretty happy with the overclock if it runs @ 1.5 i would be a bit disapointed.

But how do i find out?

And it would be interesting if HD6770 owners can select higher clock speeds for the shaders because of its higher base speed.

I also updated the graphics driver to 11.6 and i believe this makes a huge difference.

 

[SnorLars]

So if the memory of my HD6750m runs at 1.35v im pretty happy with the overclock if it runs @ 1.5 i would be a bit disapointed.

But how do i find out?

GPU-Z

I also updated the graphics driver to 11.6 and i believe this makes a huge difference.

I've tried every driver version between 8.812.0.0 (11.1) that came with boot camp and 8.860.0.0 (11.6) and it doesn't make any difference in fps for me at all. Wonder if I need to do a complete uninstall but dunno how to in boot camp.

 

[A Macbook Pro]

I also didn't get an FPS difference either, but I assume that's because they optimize some games in graphics drivers and they're the ones that see change. For example Battlefield 3 on the current drivers and drivers that come out a month after its release should see an FPS difference.

 

[Kerel]

CPU-Z doesn't give any voltage info of the vram.

I did not extensively test the difference between the original bootcamp drivers and the Catalyst 11.6. ones but i thought i noticed some difference in Stalker CoP. But the differences probably vary between titles.

 

[ambaris87]

Have you tried using any different drivers? I'm not sure if Im going to overclock but I definately want to check the temperatures and use fan control as I find it's getting pretty hot.

I'm running Win 7 with the same iMac set up

I've been able to run Crysis 2 on the higest settings without any framrate issues.

Wither 2 seems very demanding though, it runs around 35 fps on high settings at max resolution, but it has it's slowdowns.

What iMac setup do you have. I have a new 21" just instaled another 4gigs and I can barely run the witcher 2 on medium settings . When I emailed the tech guys behind witcher 2 they said its because the iMac graphics werent that good for it. Thats hard to believe when I can run other games at high or max settings no problem like Starcraft 2.

 

[A Macbook Pro]

What iMac setup do you have. I have a new 21" just instaled another 4gigs and I can barely run the witcher 2 on medium settings . When I emailed the tech guys behind witcher 2 they said its because the iMac graphics werent that good for it. Thats hard to believe when I can run other games at high or max settings no problem like Starcraft 2.

The graphics in the 21'', especially the base model, is pretty bad. Some games aren't done well and take up more resources then they should. Witcher 2 might be an example of this. All you can do is slightly overclock, keep your graphics drivers up to date, and keep the game up to date.

My 6970M 2GB is absolutely flying with the latest drivers. It's even demolishing Crysis 2 at pretty good settings.

 

[aliensporebomb]

Well

Interesting. My big deal is Xplane - I don't care about the highest possible resolution since there isn't a computer that exists that can run it at full res with all settings without it becoming a slideshow.

But it would be neat to see if I can push this thing a little. I also have another idea but installing Win7 and giving up 300 gigs of space to do it is a little egregious. Maybe if I had a 2 gig internal drive.

 

[SnorLars]

I read about a guys who pushed the 6970M to 895/1100.
I tried that but was unstable so I ended up at 860/1100 which seems to be stable...so far. :-D

I'm new to 3DMark but downloaded the free version and ran it. Got a score of 21184 which is almost the same as for a NVIDIA GeForce GTX 580 desktop card (21429).
I compare results here.

If anyone has a better way to compare graphicscards then please tell me.


My problem now is temps. Got my iMac wallmounted in the livingroom and fanspeeds are on the limit of what my wife accept. Still the temps are too high for comfort.
So I got me a 120mm casefan which I power via USB and put it on the wall to the left behind the iMac. Temps are lower and the casing is much cooler so gonna go for another one.

I'll be back with more info.

 

[jackoatmon]

Hello. Thanks for the great thread.

I have one issue though. Anyone else having troubles getting SMC fancontrol to work? First it was giving me an error that the fanspeeds were too low compared to the minimum so it couldn't proceed. Now it's disappearing after a few seconds of being on the screen.

Any advice/different fan control program?

 

[mattkidd]

Managed to OC my 6750m to a stable clock. Currently runs incredibly stable at 855/1000 at 1.055v. Fans are set to half speed with temps no more than 55, fans on full stays under 40.

Huge improvement in all my games

 

[jackoatmon]

OK! I got it going.

Big thanks to SwarleyStinson for his test specs and app reccs!

I used the "conservative overclock" settings for fan and gpu, and it made one hell of a difference in FPS on The Witcher 2. At 2560x1440 with most things on except bloom/AA/high quality shadows, I went from like 22FPS to a solid 30 during action scenes. Totally playable and at huge res, on what I consider to be the best game graphics ever made to this point (Witcher 2 really pushed the envelope BTW if you haven't seen it yet).

Can't wait to do more tests!

 

[JInx3110]

drivers

the AMD 11.8b driver works well on my 6970m 2gb, got all kinds of problems in-game with 11.6 and whatever one comes with bootcamp.

I think a conservative OC to the 6850 level will suit me, thanks for the tip about setting fans in osx btw

 

[NMF]

Ok, I figured out how to use the fan control thing in Windows... but how do I get my normal fan speeds back? Didn't the iMac used to shift them itself as needed? Now they're locked, and loud. I download SMC Fan Control for OSX and the "default" clocks are the last clocks I used with MacFan on Win7.

WTF? How do I turn this crap off?

 

[MythicFrost]

Ok, I figured out how to use the fan control thing in Windows... but how do I get my normal fan speeds back? Didn't the iMac used to shift them itself as needed? Now they're locked, and loud. I download SMC Fan Control for OSX and the "default" clocks are the last clocks I used with MacFan on Win7.

WTF? How do I turn this crap off?

Is there an option to reset your fans in SMC Fan Control? If not, make sure it doesn't run on startup and then shut down your computer and turn it on a few minutes later.

 

[NMF]

Is there an option to reset your fans in SMC Fan Control? If not, make sure it doesn't run on startup and then shut down your computer and turn it on a few minutes later.

There's an option in the OSX version, however the Win7 version changes the baseline in the firmware and cannot be reset. So when you "reset to default" in SMC it defaults back to whatever you set them as in Win7. You can go back in Win7 and manually change it back to the default speeds if you can find them online for your model... but for the 27" 2011 it wouldn't let me clock them down that low. I had to uninstall Windows, wipe Macintosh HD, and completely re-install OSX to get the fans back to stock settings.

So BE WARNED, don't mess with your fan speeds in Win7 unless you're positive you don't mind the jet engine.

 

[jackoatmon]

There's an option in the OSX version, however the Win7 version changes the baseline in the firmware and cannot be reset. So when you "reset to default" in SMC it defaults back to whatever you set them as in Win7. You can go back in Win7 and manually change it back to the default speeds if you can find them online for your model... but for the 27" 2011 it wouldn't let me clock them down that low. I had to uninstall Windows, wipe Macintosh HD, and completely re-install OSX to get the fans back to stock settings.

So BE WARNED, don't mess with your fan speeds in Win7 unless you're positive you don't mind the jet engine.

Yeah my best practice is to change it in OSX, restart into windows, then when I'm done gaming, shut down and restart manually. It's a bit obtuse, but I only game once per week or so, so it doesn't bother me. Plus I like to leave it shut down for a few minutes after overclocking to let everything cool off before starting.

 

[MythicFrost]

There's an option in the OSX version, however the Win7 version changes the baseline in the firmware and cannot be reset. So when you "reset to default" in SMC it defaults back to whatever you set them as in Win7. You can go back in Win7 and manually change it back to the default speeds if you can find them online for your model... but for the 27" 2011 it wouldn't let me clock them down that low. I had to uninstall Windows, wipe Macintosh HD, and completely re-install OSX to get the fans back to stock settings.

So BE WARNED, don't mess with your fan speeds in Win7 unless you're positive you don't mind the jet engine.

Ah, that's terrible. I only ever use SMC to change fan settings.

 

[symber]

An iMac is an all in one. You cannot built that. As all in ones go, the iMac is the best. The discussions here escalate when people effectively try to justify that an all In one is a great gaming system, and people with dedicated gaming rigs roll their eyes. I love my iMac, it's my favourite computer, but I use my gaming rig and the iMac as a display using target mode when I game. Anyone trying to convience me that the iMac is a great gaming solution has no hope as the gaming experience with all the setting at ultra at 1440p is so much better on my PC then in my iMac (I cannot max games out on an IMac at 1440p)

Hello mate. Just curious how you got your iMac to work in target display mode. Did you need a Thunderbolt PC or is there some other way of doing it? Interested in doing this myself. Any tips? (Haven't owned a PC since the Pentium I had at uni got wiped by my brother...)