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Eug Wanker · Sep 21, 2006, 11:32 PM

24" 7600GT Overclockability... - Mac Forums

7600 GT is 500 MHz core and 575 MHz memory, compared to the 560/700 one usually gets on the PC side. I could see a few reasons for this:

1) Apple cheaped out and is using cheaper components
2) Apple felt the heat generated from the GPU at higher clocks could compromise the iMac's reliability.
3) Apple felt the heat generated from the GPU at higher clocks would cause the fan to come on too often and make the iMac louder.

Dunno which is true, if any.

Anyone up for writing an overclocking app for the iMac?

P · Sep 22, 2006, 01:31 AM

3), most likely. That's what they've done before.

Simon · Sep 22, 2006, 03:17 AM

I'm with P. No. 3 seems most likely.

I'm wondering how much this influences the very modest OpenGL advantage of the 7600 over the 7300.

Pierre B. · Sep 22, 2006, 04:33 AM

I think the 24" model should have enough room to cool the GPU when running at full speed, core and memory. This would mean no reliability problems but more noise. On WinXP there must be a utility to restore the default settings. Now, who will do it?

iREZ · Sep 22, 2006, 11:45 AM

how bout marketing...so that the next revision of the imac has the new "FASTER 7600GT!!" across the board to tempt users.

enough apple conspiracy...3. makes the most sense to me out of those options.

Eriamjh · Sep 22, 2006, 12:31 PM

Don't compare the MXM version of the chip to a desktop version. Desktops have better cooling (and more noise).

eddiecatflap · Sep 22, 2006, 01:52 PM

is it that much faster than the radeon x1600 in the 20" er ?

Eug · 02:01 PM

Originally Posted by Eriamjh

Don't compare the MXM version of the chip to a desktop version. Desktops have better cooling (and more noise).

That's just it. Judging by Apple's description, this is a desktop version of the GPU. It just happens to be on an MXM or MXM-like card.

It's like they took a (cheaper?) desktop GPU and underclocked it so it's close to GeForce Go 7600 GT performance.

Anyways, that's what I was talking about n my 3rd option. They did it to keep it cool and therefore reduced potential fan noise.

Originally Posted by P

3), most likely. That's what they've done before.

Which machines?

Originally Posted by Pierre B.

I think the 24" model should have enough room to cool the GPU when running at full speed, core and memory. This would mean no reliability problems but more noise. On WinXP there must be a utility to restore the default settings. Now, who will do it?

Yeah, that would be great. Upclock it for Aperture and games, and then put it back to normal for most other usage.

Originally Posted by eddiecatflap

is it that much faster than the radeon x1600 in the 20" er ?

Yes. Here is a Cinebench test comparing the 7300 GT vs. the X1600, both running Mac OS X 10.4.7 on a 2.16 GHz Core 2 Duo Merom CPU. The 7300 GT beats the X1600, but is a slower GPU than the 7600 GT.

Processor : 24" iMac Core 2 Duo
MHz : 2.16 GHz
Number of CPUs : 2
Operating System : Mac OS X 10.4.7
Graphics Card : NVIDIA GeForce 7300 GT
Resolution : 1920 x 1200
Color Depth : 32-bit Color
Rendering (Single CPU): 359 CB-CPU
Rendering (Multiple CPU): 659 CB-CPU
Multiprocessor Speedup: 1.83
Shading (CINEMA 4D) : 441 CB-GFX
Shading (OpenGL Software Lighting) : 1759 CB-GFX
Shading (OpenGL Hardware Lighting) : 4134 CB-GFX
OpenGL Speedup: 9.39

Processor : iMac Core 2 Duo
MHz : 2160 (2.16 GHz)
Number of CPUs (cores) : 2
Operating System : 10.4.7
Graphics Card : X1600, 128mb
Resolution :
Color Depth :
Rendering (Single CPU): 359 CB-CPU
Rendering (Multiple CPU): 675 CB-CPU
Multiprocessor Speedup: 1.88
Shading (CINEMA 4D) : 438 CB-GFX
Shading (OpenGL Software Lighting) : 1658 CB-GFX
Shading (OpenGL Hardware Lighting) : 3493 CB-GFX
OpenGL Speedup: 7.97

P · Sep 22, 2006, 02:18 PM

Apple downclocked the Radeon 9600 in the iMac G5 Rev B to something around 9600 Mobility levels, not "regular" which what you would think from the name. More recently, the X1600 GPU in the Macbook Pro was underclocked.

Eug · Sep 22, 2006, 02:36 PM

Originally Posted by P

Apple downclocked the Radeon 9600 in the iMac G5 Rev B to something around 9600 Mobility levels, not "regular" which what you would think from the name.

That's incorrect. The Radeon 9600 in my iMac G5 2.0 is 325/200, which is what ATI lists on their website.

More recently, the X1600 GPU in the Macbook Pro was underclocked.

Yeah, that's quite the massive underclock.

quiklee · Sep 22, 2006, 02:45 PM

I would say No. 3 since Jobs really cares about overall satisfaction of the computer . . . plus this computer is aimed at the average computer user who doesn't care much to upgrade or anything like that . . . isn't that apple's MO?

it's like buying a corvette and complaining about the stock exhaust when you could of gone to buy a used mustang to fix up which would probably kill the vette!

Eug · Sep 22, 2006, 02:54 PM

Originally Posted by quiklee

plus this computer is aimed at the average computer user

The 1920x1200 24" iMac with 7600 GT is aimed at the average computer user?

it's like buying a corvette and complaining about the stock exhaust when you could of gone to buy a used mustang to fix up which would probably kill the vette!

I dislike both Corvettes and Mustangs.

Eug · Sep 22, 2006, 04:33 PM

In case anyone is interested: How to enable Coolbits on XP

Chuckit · Sep 22, 2006, 04:37 PM

Originally Posted by Eug

The 1920x1200 24" iMac with 7600 GT is aimed at the average computer user?

It's not aimed at pros.

Eug · Sep 22, 2006, 04:43 PM

Originally Posted by Chuckit

It's not aimed at pros.

I agree, it seems to be aimed at neither the pro market nor the average consumer. It's more a 'prosumer' machine, although some pros may buy it (many in fact, judging by posts around the net), and some average consumers may buy it.

mduell · Sep 22, 2006, 04:54 PM

It would be news if any Mac graphics card ran at the stock frequency.

I believe they're all underclocked.

Maybe the 17" MBP is at stock speeds...

Eug · Sep 22, 2006, 05:02 PM

Originally Posted by mduell

It would be news if any Mac graphics card ran at the stock frequency.

I believe they're all underclocked.

Maybe the 17" MBP is at stock speeds...

Check my post above. My iMac G5 2.0's Radeon 9600 runs at stock frequency.

P · Sep 23, 2006, 09:58 AM

Originally Posted by Eug

That's incorrect. The Radeon 9600 in my iMac G5 2.0 is 325/200, which is what ATI lists on their website.

Interesting. I got the idea from this article:

iMac G5/2.0GHz versus others

but it seems he is wrong, and the regular Radeon has the same clockspeed as the mobility one.

Leonard · Sep 23, 2006, 10:31 AM

Originally Posted by mduell

It would be news if any Mac graphics card ran at the stock frequency.

I believe they're all underclocked.

Maybe the 17" MBP is at stock speeds...

I couldn't agree more with you.

People always seem surprised by this. Or, if it's not underclocked, then it's got to be cooled and people are complaining of noise.