Undervolting / Underclocking the KHLB2 HD 4650?

The HD 4650 in my KHLB2 is a bit warm.

When idling it sits around 57 C, and goes up to 75 C when being used. For comparison, my p8600 CPU idles at 39 C.

I've already applied AS5 to the GPU but it still causes the fan to turn into a jet engine.

Is there any way to undervolt or underclock it? I've tried using RivaTuner and ATITool but none of them give me the option. I am using Catalyst 9.9 .

 

GPUs automatically underclock and undervolt. Download PowerMizer (search NBR) to check if its activated. I suggest you undervolt your CPU since the heat is tied to the whole system and will lower help lower temps across the entire notebook. Underclocking is generally useless since it's mainly voltage that causes the most heat (though in extreme cases, underclocking will lower the temps a bit).

 

As fas as I know you can only undervolt via bios modding. The HD 4650 should be able to handle the max clocks @ 1.0 V (instead of the stock 1.1 V). I tried undervolting my HD 3650, but it doesnt really work.

Anyway if 75°C is the peak temp of your GPU under hours of full load then dont bother with undervolting, it's a very good value and the fan is just loud in the KHLB2... undervolting will not solve that problem I fear.

 

I've also undervolted/underclocked the CPU and applied AS5. Underclocking helps less than undervolting, but it still helps!

Also isn't PowerMizer for Nvidia only?

Is there a safe and proven way to bios mod the 4650 in the KHLB2? I'm really not liking the fan. My last laptop, a cheap Dell with an 8600 GT, had a huge heat sink compared to this one and the fan was never this loud

 

Sorry misread your GPU, PowerMizer is for nVidia. There is always risk in modding, maybe consider an external laptop cooler if you want a safe way to lower temps.

 

There is always the risk that somethings goes wrong during flashing, but still the process does not take that long and even something like a power outage that would pose a problem with a Desktop PC will not bother you.

Create a bootable USB drive and then download atiflash. Then get the Bios from you card and try to modify it. It is relatively save since you can and should leave the boot values for the card untouched, so you can ensure that you can at least revert the changes if the clocks or VCore values are not working under Windows. However at the stock clocks you should be able to reduce the VCore from 1.1 to 1.0 for high performance modes - someone in this forum did that. You can also downclock the clock settings for battery saving mode by 10 - 20%. Just keep a backup of the original bios and never change the boot values.

The fan speed is most likely regulated by the normal bios which afaik cannot be edited on Compal laptops. Loudness is a huge factor for me when buying a laptop, you should always check that beforehand... I used to have a very loud laptop, but at least it's only very noticeable if the laptop is under load, e.g. when playing and then you can always use a good headset with good insulation - in the end that proved to be the best solution for me.

 

I tried using GPU-Z to extract the bios but the program said "Bios reading not supported on this device".

Anyone have any experience with this?

 

I don't think you can extract the VBios under Windows.

Just boot from USB device and use Atiflash to receive the VBios. Then modify with Radeon Bios Editor under Windows, save the VBios on the USB device, reboot from the USB device and overwrite the original VBios with the Version modified by you. It's the easiest way to do it and the savest, even if there was a way to modify the VBios directly via Windows, I would not recommend it.

 

I just tried using Atiflash and I had the same problem.

I tried to force dump the bios by typing "atiflash -s 0 test.bin 10000" because "atiflash -i" showed the size being 10000. It dumped a file of all null bytes.

I thought that maybe my device just doesn't support a bios dump, but then I found this link http://www.techpowerup.com/gpuz/3hu9c/ This is the exact same data I get when running GPU-Z but I am unable to dump/report it because it says the "device is not supported". I wonder how this person was able to do it.

Any KHLB2 owners out there?

 

Stupid question: Did you try dumping it with just "atiflash -s 0 bios.rom"? Anyway, the problem could be that - just as with the stock 8600M GT in the FL 90 - the VBios is incorporated into the system bios. That would suck, cuz nobody seems to be able to modify that one.

Anyway, you really should be happy with your laptop as it is, if 75°C really is your peak temperature after hours of gaming then your good to go.

 

Yes I tried that first. It refused to save. I'm not bothered by the temperature at all. It feels about as warm as my old Dell with a 8600 GT. The problem is the fan that sounds like a jet engine

 

Yeah, but thats because it is one of the small fast spinning fans cuz it's a realatively small laptop. Those fans produce such noicy jet engine like sound... was the same with my old laptop... I'm afraid that can't be helped, if the undervolting of the CPU didn't make it any better.

However, when playing Games you can use a Headset or tune up the volume to counter the problem and while using the Laptop for office stuff just switch to battery saving mode which reduces the fan speed greatly.

I now managed to undervolt my HD 3650 by 0.1 Volt but it makes no difference at all, however, undervolting my T7500 from 1.25 V to 1.0125 V helped reduce the noise from the fan A LOT.

 

I actually looked at the notebookreview review. They said it was relatively quiet at 34 db. I never thought of a 15.6" laptop as small though.

What I found is that I can tolerate the sound when the fan is spinning at low speed, but once the temperature goes over 70, it becomes too loud. If the cpu is any indicator, I thought it would be possible to undervolt it down to that level.

 

True, thats what I read as well, but sometime you cannot notice such when you use a laptop only for a couple of hours or even days. The db value alone indicates not much since it says nothing about how noticeable the sound actually will be for you. The fans of big notebooks produce higher db values but since they spin at a lower speed they are much more comftable to hear than fast spinning small fans that produce fewer db.

Anyway, I thought you undervolted your CPU and the P8600 runs at much lower voltages anyway... don't think that you can reduce it much further.

I fear you have to live with it or use a headset... as I said, even if there was a possibilty to lower the fan speed, i would not recommend it as it will drastically increase the heat.