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redexredex
09-25-2014, 09:21 AM
Hi,

I'm thinking about overclocking my G750JZ's 880M GPU without doing any modifications to my laptop.

Is there any thread already where people are showing their stable overclocking results?
I'll need some hint about how much i'm supposed to overclock my GPU and GPU's memory.

Thank you.

redexredex
10-10-2014, 04:51 PM
Anyone?

hmscott
10-10-2014, 07:33 PM
Anyone?

redexredex, there are several guys who have OC'd their JZ, you just need to give them more time to respond :)

I have the JH, so I can help you with the CPU - it's the same, and the GPU I can also help with the technique, but not the values to OC... you can try searching through the forum until they respond.

To speed up the CPU, it really isn't an OC per se, it is increasing the Core and Cache multipliers to the max allowed by Intel Extreme Tuning Utility, XTU.

Intel Extreme Tuning Utility - XTU 5.1.0.23 current version
https://downloadcenter.intel.com/SearchResult.aspx?lang=eng&keyword=xtu

Use XTU to set the Cores to 36x,35x,34x,34x and the CPU memory cache to 36x, do this in the Tuning area of XTU, then Apply the settings, then save them as a Profile you name - so XTU will set the change at each reboot. If you crash for any reason, likely not the XTU multiplier settings, XTU won't apply the settings at the next reboot - you need to go in and select the Profile, and Apply again.

What can cause XTU to BSOD is the next tuning parameters, the negative voltage offset. You want to do this to reduce the heat generated by the CPU - especially important in the JM/JS/JZ as they have enabled the Intel GPU - which raises CPU temps +10c from the JW/JX/JH averages.

Here are the settings with multipliers (5 settings) set and a -25mV voltage offset (2 settings) set.

41984

The range of successful voltage offsets are -20mV to -125mV - the larger the drop, the less heat generated. You can start at either end depending on your technique. I start high, get a BSOD, raise number 25mV (say from -125mV to -100mV) until I am stable without BSOD during a load test - your favorite CPU 100% utilization test, then the last test is stable at idle - if you are stable at load, leave it idle for an hour, and see if it BSOD's on it's own - then increase by 5mV at a time till completely stable.

My JW run stable at -125mV, JX at -70mV, JH was stable initially at -20mV, but now is stable at -50mV - I retest every couple of months.

Be sure and not do any important work while finding the stable undervolt - you can change over to the default profile when you need to be 100% stable until you find the right voltage.

After you do this we can move on to the GPU :)

I should mention that the 880m is an already overclocked 780m, with a new vBIOS for more voltage and higher frequency for GPU / memory. There isn't much headroom available for additional 880m over clocking, so don't be surprised if it won't do much more.

Here are my OC settings for the 780m in the JH

41985

The JZ/JS/JM use a different Asus Tweak for Laptops, and a different version number as well. It looks like this:

41986

Here are some details for the Tweak tools, for both series:

Asus GPU Tweak for Laptops vs Asus GPU Tweak for Graphics Cards
http://rog.asus.com/forum/showthread.php?45644-Asus-GPU-Tweak-for-Laptops-vs-Asus-GPU-Tweak-for-Graphics-Cards&p=387929&viewfull=1#post387929

Have fun :)