6750M - Clock difference between 15" & 17"?

Hello Everyone.

As the title says, I am trying to figure out if there is a difference between the clock speeds of the 6750m on the 15" and 17" 2011 MBP.

I could not find a program to read the values in OSX, so in bootcamp I used gpu-z and it shows the clocks to be:
GPU = 600
MEM = 794 (basically 800)

The core is at what ATI says is stock (600mhz) for this chip but the memory is 100mhz lower (stock should be 900mhz).

So, I was wondering if Apple did this on just the 15" or if they did the same on the 17".

Also, I noticed that (according to HWiNFO32) that while the card is seen as a 6750M, the chipset is seen as a 6650M.
I know that the only real difference between the 6650m and the 6750m is that the 6650m uses DDR3 ram while the 6750m uses DDR5 so no huge surprise there.

But, one small (possible) caveat is that when installing reference drivers from ATI (ie.. 11.4 beta etc) that it will see your card as a 6600m series.

1002&DEV_6741 is the Hardware ID (which corresponds with the 6600M series)

Now, it is easy enough to change the Device ID to anything you want (I changed mine to 6750M Apple) but it still makes me wonder if when the drivers are being installed they are being configured more toward the 6600m series cards instead of the 6700m series.

Now, I can easily OC the memory to the reference 900mhz (in windows) but am just curious about the 17" and what the memory timings are.
I may have to take a teardown look at the 17" and see what (if any) logic board differences there are between the two.

Any thoughts?

D.

 

Good question, but if the core clock is already at reference, I doubt Apple would bother differentiating the models if they felt the heat was already acceptable for the 15" model.

 

True.
I am sure the core speed is the same between both, but I do wonder about the memory (since the 15" is 100mhz below stock).

Anyone with a 17" willing to run gpuz on their bootcamp partition and tell me?

D.

 

will do tomorrow. I'm stuck running tests on this new memory and I need to be in OSX to do so.

 

Cool, let me know once you get a chance.

D.

 

Not to rush you but... did you have a chance to check yet... I would love to know as well.

 

Thanks ajreynol

Looks like the stock clocks are the same on the 15" and 17" (mem 100mhz below manufacturer stock)

D.

 

no problem.

 

^ The 17" is the same exact chip as the 15" then.

 

gpu memory doesn't scale right?

 

reword the question?

 

You don't understand or you're trolling?

Does the GDDR5 memory in the 2011 Macbook Pro's AMD 6750M scale depending on load? I don't have bootcamp installed and I can't remember if my previous cards did.

 

I very much doubt he would be trolling. He's usually (always, I'd say... but with 2,400 posts, I haven't read them all) very helpful and has a good predisposition.

On to the topic, the GPU has 1 GB of dedicated memory. It will not always use it all. It depends on usage. I believe it can access more from the general system memory if it needs it, but it's been generally considered a gimmick.
If it's raw power and performance you're speaking of, then yes, it will scale will necessity and power profile ("high performance", "maximum battery", etc.).

I hope this answers your question

 

^ yea, pretty much. it uses as much of its dedicated memory as the application you're running demands. No more and no less.

I really didn't understand the question.

 

My fault then, must have been a bad day.


Memory clocks scale based on load.

The reason there is a 100Mhz difference compared to the reference card could be due to the memory clock scaling.

Can someone do another GPUZ test with full load on the gpu?

 

I don't think you quite get what we are talking about.
The 15" and 17" run at 100mhz gpu and 150mhz memory when not in load.
When in load it runs at 600mhz cpu and 794mhz memory when in load.

When we are talking about stocks we are talking about what the max speed of cpu/mem is default (load) compared to ati reference speed (where the memory is 100mhz below reference)

D.

 

What is the difference in GPU Clock and Default Clock then?

 

They are the same.

Here are the Default (Stock) clocks ATI has for the 6750M
GPU = 600mhz
Mem = 900mhz

Here are the defaults Apple has for the 6750M
GPU = 600mhz
Mem = 794mhz

SO, Apple has default (stock) clocks on the gpu but the memory is 100mhz below default (stock).

These speeds are (of course) when the card is at full.
If you enable powerplay the card goes to a low power state of:
GPU = 100mhz
Mem = 150mhz

These low power speeds are the same between ATI default (stock) and Apple

Hope this clears things up

D.

 

Where are you getting your specs from?

AFAIK even the 6770 in the HP machine comes at 725/800.

EDIT: http://www.amd.com/us/products/note...00m-6600m/Pages/amd-radeon-6700m-6600m.aspx#2

Memory clock speed: 800-900 MHz GDDR5 or DDR3
Memory data rate: 3.2-3.6 Gbps GDDR5 or 1.6-1.8 Gbps DDR3
Memory bandwidth: 51.2-57.6 GB/sec (GDDR5) or 25.6-28.8 GB/sec (DDR3)

You can get low power (1.35v vs 1.5V) GDDR5 at 800mhz, I think that's why it's popular.

Also considering that the 66x0 and 67x0 use the same chip, why would they use different drivers?

 

the specs come from GPU-Z, Afterburner, ATITrayTool. They all are very clear.



Pay special attention to the "Default Clock" speeds. It also runs at a max of 1.000V.

Assuming all clocks are stock:

when in low-power state (most of the time), the GPU will be running at 100/150. the system will be quiet and the GPU will be relaxing in the 50C range.

when the GPU is requested to be under load (say, gaming), it ramps up to its maximum speed of 600/794 and stays there. the temps will go up into the low to mid 80s C. When you quit the game/application, the GPU will immediately go back to its low-power state, GPU temps will drop, and the world is wonderful.

Now, you can disable its low-power state and have it run at max power 100% of the time. When not under load, the temps will still be low, but not as low as the 100/150 setup. I don't believe there is any consequence to doing this other than perhaps a bit shorter battery life and a slightly higher temp.

Of course, you can overclock and overvolt if you wish.

 

talking about the numbers in GPUz.
it says

GPU clock 750 MHz Memory 925MHz
Default clock 600 MHz memory 794 MHz

its almost like its saying its running 750/925 max, but default should be less... but its basing it off the misidentified card Radeon HD 6600M series. So i'm wondering what that GPU clock entry means if its not the actual GPU clock.

 

That screenshot shows an overclocked GPU.

The stock clocks are 600/800 (basically) while someone has overclocked it to 750/925.

That screen shows current 3d settings, the sensor tab shows the real time clocks.

For example on my 5730:





Note: I have flashed the bios to 875/1100 clocks.

 

... ... ...

 

So if it's so plain what is your problem?

Of course by specs I meant the clocks you expected, not the ones right in front of you.

Stock clocks are 600/800 which is within the range given by AMD meaning your card is stock and not underclocked.

The reason I was being so obvious is that you have to be missing something obvious if you are still having issues understanding that.

Also btw, disabling the low power state is a stupid thing to do.

 

that makes more sense then.. had no idea you overclocked it. I also have barely used Windows more than maybe 4 hours in the last 2 years, and never used gpuz before, so wasn't familiar with how it listed things.

 

No, I understood. I was asking because I didn't have bootcamp loaded so I was wondering what the scaling was like in order to explain the 794mhz memory clock vs the 900mhz memory clock maximum from ati's website.

100mhz was the difference between ati's reference and our listed memory speed.

Anyways all seems to be clear here.

 

Yes its the maximum, but ATI list that 800-900mhz is normal.