Recently, I reviewed the Apollo nVidia 6600GT. During the research for that review, I found out that the chipset on all 6600GT's has an onboard temperature sensor, but many card manufacturers opted not to enable temp monitoring on their particular cards. I would assume to discourage overclocking, but I'm just guessing.
I'm not really that big on overclocking video cards, but you've always got to try it, even if you don't leave it that way. And anyway, this is the OVERCLOCK Intelligence Agency. But, even if I don't overclock, if the sensor is there, I want to use it.
So, while I was researching for the review, not only did I find out that there is a sensor there, I also found out that you can enable it. I got this information from threads on the subject at nVidia Forums, and at MVKTech Forums. It definitely wasn't my idea, as I am by no means a programmer. I'm just passing along information that worked for me.
Temp monitoring is found on the nVidia 6600GT control panel... which is found by right-clicking on any open area on the desktop, Properties, Settings, Advanced, geForce 6600GT, Temperature Settings. If Temp monitoring is not enabled on your card, you will not see the "Temperature Settings" on the control panel.
So, your control panel looks like this, and you want to know, "How do I enable temperature monitoring? Well, you have to mod the card's BIOS. Yes, it is kind of scary, and not for the squeamish, because face it, it would really suck to kill that new video card that you shelled out your hard-earned cash for (or the cash that your grandma gave you for your birthday.
The instructions that I am going to give are Windows 2000/XP specific, and worked on the Apollo 6600GT. It has also worked on cards from many other brands, including AOpen, Albatron, Asus, BFG, Club3D, eVGA, Galaxy, Gigabyte, Inno3D, Leadtek, MSI, Palit, PNY, Rosewill, Sparkle, and XFX; and other O/S, follow the above forum links for a list of cards it has worked on, and further instructions for Windows 9X.
You will need the following items:
a floppy disk (all data presently on the floppy will be erased)
a hex editor, I used XVI32
You will need to be able to extract a .zip file, I used the extractor already in Windows XP
NOTICE: This is not a terribly difficult task, but the instructions have to be followed carefully. If you really think you shouldn't be doing this, by all means DO NOT CONTINUE!
I highly recommend printing out these instructions. I usually just highlight and copy stuff, paste it on Notepad, and print it.
1. Create a boot disk containing nvFlash 513.
Stick a floppy in A: drive.
Launch DRD Flash.
Click "OK" (the boot disk image will be written to the floppy)
Extract nvFlash to A:
2. Save a copy of the BIOS to the floppy.
Make sure that your mobo BIOS is set to boot from floppy. You may have to go into your BIOS and make the floppy the first boot device.
Insert the boot disk you just created in A:
Restart your computer.
Type “Nvflash –b biosback.rom” and hit enter.
Your card's BIOS will now be saved to the floppy. When it is finished, remove the floppy and restart your computer.
3. Editing the BIOS.
Extract XVI32 to a location where you can find it. Open the folder.
Double-click on XVI32. Click "run".
Insert the floppy in A:.
press "Ctrl" "o"
open "biosback.rom". It is in A: if the program didn't automatically take you there.
Click "tools". "Text mode" will probably be checked. Click on it to uncheck it. The left side (hex side) of the page should now be white.
click "search" "find" "hex string"
Type in "04031201"
Click "OK". The "04" should be highlighted.
Immediately after the "04 03 12 01" should be "10 0A 01 11"
WARNING! If the string "10 0A 01 11" is not immediately after the string "04 03 12 01" STOP!!! DO NOT CONTINUE. You cannot perform this mod on your particular card! It probably can be performed, but not by these instructions.
Highlight the "10" that is immediately after the "01". Change it to "00"
The entire sequence should look like "04 03 12 01 00 0A 01 11"
Click "file" "save as" and save the modded bios as something simple. "biosmod.rom" is what I used. We want to leave the "biosback.rom" intact for obvious reasons.
4. Flash the card with the modded BIOS
Leaving the floppy you just created in A:, restart your computer and let it boot from floppy.
Type "nvflash -5 -6 biosmod.rom". Hit enter.
Press "Y" if you are prompted to.
When nvFlash finishes flashing the BIOS, remove the floppy, and restart your computer.
You should now be able to monitor your temps.
I would like to thank the guys at nVidia Forums (especially Symbios) and MVKTech Forums for the information that made this article possible.