Getting Ready For Modification First the back of the 8600GT and GTS are held together by 4 holding screws that hold the cooler on. You can use a small flathead or small Phillips screwdriver to get the screws out. After the screws are out with a little nudge the cooler will come off.... After this if you look at the bottom you see a pretty flat copper base. Now its really important you take a second to see were the Thermal paste is on the cooler. This is important because you should mark with a pencil or simply remember were it is. Ill run you through how to lap it. After you remove and and memorize/mark were the paste was on the cooler take alcohol 70% iso. Or more and some q-tips and remove the old stock gunk. After its clean take 2000 grit sand paper and start sanding the area the core touched on the cooler. When its really really smooth and shiny your done when you think you cant get any better. Ok So now that thats done take some Arctic silver 5 Arctic Ceramique or MX-1/2 and squirt it on the core and a small dot on each of the memory chips. This makes sure that the memory is properly cooled and this isnt the stock stuff so were ready for over clocking!!!! After you put the cooler back on make sure you tighten it down really tight alternating screws in a pattern. Until they wont tighten anymore. Ill leave it to your discretion to know how tight but know if you tighten it to much you may damage the card severely. Riva Tuner Tweakage: Ok first off you just got your brand spanky new 8600GT or GTS or you've had it for awhile and you want to make it faster. Well the first thing you want to get is Rivatuner This nifty little program allows you to: Overclock the Core, Memory and shader clocks. Adjust Fan control unlock pipes (not available on 8600) temp monitoring plus much more. Ok first off lets open up Rivatuner. This is what she looks like. First off under Driver settings click on the customize arrow to reveal A icon that looks like a grfx card and says System settings when hovering over it. After clicking on the button you get the good stuff yes here we go the overclocking settings! So with no Volt mods as you can see she already clocks up a respectable amount from the default 540/1188/700. I choose not to link the shaders to the core (They are by default) because clocking the shaders up more improves performance than leaving them linked. For example clocking the core to 600 would allow the shaders to go higher improving performance. However I like all my clocks high so thats why I top them all. The only odd thing is with the memory with no extra voltage on my particular card she doesn't like to clock very high. Maybe an extra 50 MHz at the most. Ok the other options in rivatuner are self explanatory. Fan settings etc can be double clicked on allowing you to edit the numeric entry such as 100%. If their are any questions I will gladly explain them and change/update the guide as soon as a question arises. As for Overclocking you'll have to play with it to find your max stable overclock as many cards are different. For example some cards will hit 820 on the mem default were as mine can hit like 750. With you max Oc now in place its time for a quick look at a very important setting for all OCers. FAN SETTINGS!!!! First go back to the overclock window were you adjusted your shader,memory and core clocks... At the top their are tabs you want to click the one that says fan. This is 1 of the first 2 places were going to go to make sure your new OC is stable and cool. First make sure the drop down menu is set to "Direct control". Then take all the slide arrows and move them to 100% you can make sure its at 100 and not like 97% by the real time adjuster to the left. Then after hitting the apply button save it using the floppy button next to the fan symbol at the bottom of the window. After you've saved a profile check the box "Apply at windows startup". Our next window can be accessed by the main window showing your forceware version and card type. After clicking the down arrow like the Overclocking window their will be an icon that looks like a grfx card. Click on this to get to the fan control tab. After the window opens click "Open Low-Level fan control" Doing this will unlock the options below. After you do this move the slider to 100% then check the box that says "Fixed Duty Cycle" then check the Box that says "Apply at windows startup". and then check apply. Then click ok. Then ok again to quite Rivatuner. Our tweaks here are complete for now. Voltage Modification So you've found your max Overclock But now how bout we push it a little further? Especially with the right cooling and the max stock Oc already obtained its time we push our cheap little beauty a little further. First Ill be stealing our pics from VR-zone because my card isn't currently outside of the computer. However I will be changing that soon. First off to do a cheap mini mod we need to have conductive ink or a .5mm mechanical pencil. This is because were going to need to bypass the current flow of a couple transistors. heres a quick pick of whats to come. The Inno3D pictured here has the same layout as the leadtek and windfast versions so you'll want to follow this pic. MSI Version (same as Palit Version) Now this is a Palit 8600GT which has the same layout as the evga and nvidia 8600GT GPU volt mod memory voltmod XFX edition Mem Vmod on left Core Vmod on right Now by ground (If your using the resistors) doesn't have to be a spot on the card you can ground it directly to the case. However if you want to ground to the card to keep stray wires from floating about your case you can ground them to the screw that holds the card in place, or the screws that hold the cooler on or the screw located here that holds the dvi connectors on. Now using a resistor will allow you more voltage .5v or more added over the pencil mod. Using the pencil mod will get you between 1.6 and 1.7 Core and 2.2 to 2.225 on the mem. using the transistor mod in conjunction with the pencil mod will get you much more. 1.75-1.85 on core up tp 2.5 on mem. This is dangerous but will work. I have verified this but things get HOTTT you have to watch things when you volt mod this much seeing as though you may have good cooling the transistors and resistors that are also linked to the core and voltage get extremely HOT that can lead to card failure short life span and damage. Now another way to volt mod if you want EVEN more voltage is a PSU mod. Now the nvidia and evga cards don't benefit from this to my knowledge seeing as their is a coil here. Though it may not be safe if the 6 pin solder points are on the other side it may be possible but at any rate on with the leadtek flavors. Now with the leadtek and other similar pcb layout company's their is no black box here instead you have an open 6 pin grid. Now with these pins exposed you can modify the 8600GT to accept more voltage just like its bigger brothers that need a 6 pin adapter. You can solder a 6pin plug onto this bare spot from a dead card etc and simply plug in a 6 pin adapter like this. you can also do this mod instead of the resistor or pencil mods. or in conjunction to add more power though a different form of cooling is necessary at this point. Another way is hard moding wires to the pins themselves and then connecting them to the 6 pin on your psu. Like so as you can see its set up something like this (-) negative (+) positive l + l l l + Then you simply match the colors of the wire and splice the wire or shove them in the hole of your 6pin connector. Ok and thats it so far for voltage modification, but it will be brought up a little bit later. Bios Modification Well you still want more? Fair enough. The next step is Bios modification for those ppl who really need all they can get without liquid nitrogen. First before we get started i have a couple of links and other things to say.... 1.Dude honestly i know if your reading this it was no accident you'd have to know exactly what you googled to find this thread. So ill lay it down quick. This is DANGEROUS if you flash wrong 1. instant artifacts. 2. unstable settings/card 3.$300 paper weight and a seriously pissed wife. 2.After you get passed your jitters its actually pretty easy you have to have some knowledge but alot of common sense. In the end it usually comes out fine and your very happy with your performance and very proud that YOU did it. 3. Don't blame me this is all at your own risk stuff. Even the Over Clocking I'm just someone who worked up the nut to do it you can stop now its not to late the button to do so is located at the top right of your screen and labeled (X) Now that thats done lets begin. You'll need a couple programs first. One is NiBiTor a bios editing program for nvidia cards. You can get this here http://www.softpedia.com/get/Tweak/Video-Tweak/NVIDIA-BIOS-Editor.shtml Next you'll need a flashing program called nvflash located here http://www.softpedia.com/get/Tweak/Video-Tweak/nVFlash.shtml Now with those 2 programs in hand before we prep to flash or mod a bios we need to make a startup disk. Using a floppy or CD well try the floppy first. Start by putting a floppy in your drive with wright protection off. With that done we need to format it go to my computer and right click on your drive A (floppy) after that select the "Format" command then click the box that says "Create MS DOS start up disk" then click ok and let it format. Now that thats done we need to add the nvflash programs called "cwsdpmi" and "nvFlash" in the folder you unzipped these need to be copied to the floppy disk. After this its time to boot nibitor and mod that bios!!! First open it up go to the tools menu select read bios and click on the "select device" option. After that your card will come up just hit ok. At this point and go back to the tools menu. Go through the same process tools>read bios> now select "into nibitor" you should then get a screen that looks similar to this. Congratulations your bios is now ready to be modded. Keep in mind your doing nothing to the card just yet. Its simply loaded into the computer and is open for modification. Now lets make some simple modifications. First lets change our amount of performance levels. Now by default their is only one. Changing it however will let us get away with some fun stuff like those fan and voltage over rides I was talking about. Now that we have done that 2-3 more fields will be open to you. However it wont look like mine you'll have 2 fields with a bunch of 0's you need to change these to the clocks in the one field that shows it. Like this. After that its time to move to the "Voltages" tab its time to let our card use a little more juice. If you didn't feel like modding it hard core. Ok so most 8600GT's have a 1.32 volt option with the 2d throttle being 1.2 we want to crank it up as high as it can go so I default mine at 1.32 if you don't want to thats fine but make sure your 3d and thrtl voltages are 1.32v..as for the 8600GTS yours will only show 1.3v thats fine as your card requires less power for some reason though stats iv looked up show the GTS using more watts for some reason these cards do not have a 1.32v option just set yours to 1.3. Now that we've done that inside the "Voltage" tab you'll see you are currently in one sub tab with another sub tab right next to yours called "VID Mode" click on this tab and change these voltages to 1.32 or 1.3 respectively. After this its time we change up the timings. While were here might as well squeeze the ram. Go to the "Timings" tab their you'll see a bunch of hex digits that make no sense and you'll see yours is set to "timing set 0". Were about to change that seeing as those are stock and well...slow. First click on detailed timings this brings up a screen that may look very similar to you if you clock processors and system ram. These digits are far more understandable. Alas we'll only be here for a second. what you need to do is memorize the timings real quick we need to search for a "timing set" that is faster (lower numbers) but not to fast or to slow (higher numbers) so now hit ok and it brings you back. Now were it says "timing set 0" In the drop down box we need to select a timings set and then hit "detailed timings" again after we load it to see....Iv taken the liberty for you and know its "timing set 3" after that you can click on detailed timings to see but iv also included that. Now these are not the best ones feel free to go even lower or even better entering your own values. I'm simply using this as an example to get a little performance as well as familiarizing you with the process. Ok after we have done this Why not tweak our card to represent us? Go to boot settings to see what I mean. As you can see you can change the way the card is displayed at boot. Of course if you have a card like mine you never saw it anyway, but you can change this by checking the box that says "Display Boot Messages" to the right of the screen. This allows the message with all the custom stuff you type in the box to show up as soon as you hit the power button. Now don't forget after you have typed up that glorious art known as bios stamping you want to see it right? Well theirs a cure for that to. Circled below is the time the message sits on your screen in mS (milliseconds) After this go to file in Nibitor and select save bios and save it as "new" on your floppy drive. After you save it reload your bios from your card Tools>Read Bios>into Nibitor and save this one as "orig" in your floppy drive. Now in case you screw up theirs a scape goat in sight. Now For flashing. Its simple leave the floppy in and restart the computer. I'll run you through the rest in a bit. However for you CD people its not so simple but almost i promise. Below i have taken the liberty to upload the files all thats missing is your rom files unzip these files drop your roms in the folder then save them all as an iso image so the cd boots. Over Riding Fan Settings Ok so your tired of using third party apps to control your fan settings? Well theirs a cure for that too. Go into Nibitor and load the bios you loaded b4 were going to mod it some more. this time go to the "temperatures" tab. Do to the nature of the nvidia drivers when the gpu is at a certain temp the drivers crank the fan up all the way even though when you boot it sits at 40-60%. Well we can fix this. In the pick below are your fan control settings change the fan settings in all 3-4 categories to 100%. were it says core critical the default is 115ºC well thats a little to hot for my blood so i turned the critical temp down to 1.5. After this is done re save your bios its time to FLASH!!! Flashing Ok so your ready floppys in cd's burned roms both new and old on disks now its time for the big time life or death next paycheck or dinner w/ the girl. Here are the commands i have found that have never failed me copy them on paper as i cant save you after you reboot. After you reboot you'll get a prompt that looks something like this. A:/ After this type this. A:/nvflash -4 -5 -6 file.rom were "file" is the name of your new bios...you'll get 2 prompts from nvflash at this point asking for a "Y" or "N" input to go ahead and continue. Hit Y for both of them and if you see it say it completed successfully congrats man you made it holy crap if not and you get a black screen DO NOT REBOOT wait about 1 or 2 min. then type this!!! nvflash -4 -5 -6 file.rom ware "file" is your ORIGINAL BIOS!!!! With any luck it will work wait about 10min and then reboot. If you don't see anything if the blind flash worked you'll see your boot screen etc. If not their is a serious problem your card is now in heaven. Now for the clarification with the command i provided. Their are spaces i will now show you where using an underscore. You need to put spaces at these points for the command to work. A:nvflash_-4_-5_-6_file.rom kk hope this helps all you enthusiasts out their also this guide may very well work on the 8500 series hell maybe even the 8800 depending on the layout though im leaning more tword the 8500 series if anyone has one and would like to try it out let me know so i can wright it in the blog. For anyone interested i have also included a pre modified bios that i use for my current card.