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Beginners Guides: Overclocking the Nvidia Videocard

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RedDragonXXX

Senior RAM Pornographer
Joined
Mar 3, 2005
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Jacksonville, FL
Beginners Guide: Overclocking the Nvidia Videocard

How Overclocking a Videocard Works

Videocards have three main parameters that affect their performance, the GPU core speed, video memory speed and the bandwidth of the interface between the videocard and the rest of the system (ie. AGP or PCI Express x16). There's not much that can be done about the video interface, but the core and memory speeds can both be changed, just like a computer's processor and main memory.

The videocards graphics core (or GPU) handles the actual rendering of each 3D video frame. Overclocking it obviously helps the videocard push out polygons faster, increasing overall 3D performance.

The video memory acts to the GPU as the computer's main memory does to the processor, storing video data and feeding it to the core as needed. The faster the memory goes, the less waiting around the GPU has to do, so overclocking the VRAM also has a major effect on 3D performance.

As you might have guessed though, the most dramatic gains realized when overclocking come from pushing the core and memory together, since both facets compliment each other's performance as their speed increases.


Can Overclocking Damage a Video Card?

Yes it can, but the user would have to try really HARD to do some damage, and even then it would be unlikely... but not impossible. The only way to damage a modern video card through overclocking is to set the core and memory speeds WAY higher than stock and then attempt to run benchmarks. Since most recent cards from nVidia and ATI use thermal throttling to protect the GPU from damage, even this is unlikely to hurt a newer card. If the guidelines in this guide are followed, there's no need to worry about damaging hardware.

Updating Videocard Drivers

The first thing to do before overclocking a videocard is to acquire the most recent driver set for it. NVidia's ForceWare driver sets are universal, meaning they cover most of thel recent videocards made by their respective companies. All that needs to be done is to visit the website of the card's manufacturer and download the latest version of the drivers, then install them.

You can get all the Forcware drivers here!

And for modified drivers you can grab them here!

You ask what are the modified drivers?
Modified drivers simply means that the author takes official or beta drivers from the manufacturer and starts to tweak them for either better image quality and or performance. Please bare in mind that the driver manufacturer, in this case NVIDIA, does not support drivers like these.


Benchmarking and Overclocking

To get the best out of your nVidia videocard in terms of overclocking, a consistently repeatable 3D benchmark like FutureMark's 3DMark 2001SE or 3DMark05 is needed to test the new settings each time core or memory speeds change.

Since most modern videocards run at slower speeds when rendering a 2D image such as the Windows desktop, the fact that a card can render the desktop correctly when overclocked is not a real test of its stability. To truly test an overclocked card's stability, a full-screen 3D benchmark needs to be run completely and without error.

Install 3DMark and run the (non-overclocked) system through a round of the benchmark with everything at its default setting. Record the final score. This is the baseline for comparing the video card's performance before and after overclocking.


Nvidia Overclocking

There are a couple of ways to go about overclocking an nVidia-based videocard. The most basic is to use the 'Coolbits' registry tweak built into nVidia's video drivers. Essentially, the Coolbits tweak involves adding a single value to the Windows registry which then enables core and memory overclocking within the display control panel.

You can get the latest version of Coolbits here!

To enable Coolbits you will need to add them to your registry. To do that folow these steps. First download the file and then open it up.



 
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Overclocking an nVidia card with RivaTuner

As an application which enables customers to void their warranties, the Coolbits tweak is understandably limited. NVidia does not want its customers toasting their videocards if it can be avoided.

Rivatuner is an easy to use utility that can overclock both company's cards with equal precision, and does not have the various complications that using the Coolbits tweak to overclock a video card can present.

If Coolbits has already been used for overclocking, open up the display settings and revert the video card's core and memory sliders to their default settings before proceeding further.

Once RivaTuner is installed and started, users are presented with the main screen. Video card type and driver set are displayed here, along with several other informational and settings tabs. For now, all we need is on this screen.

You can download RivaTuner here!

To begin overclocking an nVidia video card, find the box under 'driver settings' where it says 'ForceWare detected' then click the 'customize' icon. From the menu that appears, select the first icon, 'system settings'.



The first thing to do is to check the 'enable driver level hardware overclocking' box to enable the sliders below.



RivaTuner needs to determine the card's default clock settings before it can proceed. If Coolbits was used previously, make sure the card was reverted to its default settings as mentioned above. Once this has been done, click the 'detect now' button.



The overclocking sliders have been enabled, along with a 'mode' dropdown box in the upper right corner. This switches between '2d', 'low power 3d' and 'performance 3d' modes. As with Coolbits, users will be spending most of their time in the 'performance 3D' mode as there is not much point in overclocking a video card when not using 3D-intensive applications.

Now that the core clock and memory clock sliders are accessible, overclocking can begin. The two small arrows delimiting a section of each slider provide a recommended overclocking range, but the best bet is to increase the settings gradually, benchmarking at each step. As with Coolbits, each new setting must be affirmed using the 'test' button at the bottom of the window before it can be set permanently.



As with Coolbits, just because overclocked settings pass this test doesn't mean that they will work with real world games and benchmarks.
Also it is important to record your temp while stressing your video card. To do this follow the steps bellow.



And just leave this running in the background while you are runing benchmark or game, anything that will stress your video card



If your tempereature exceed 70C then I would strongly suggest that you underclock atleast untill you get better aftermarket heatsink.
 
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Nvidia Overclocking Complications: Thermal Throttling

While nVidia uses form of 'thermal throttling' in brand of GPU to stop them from being damaged by excessive heat due to overclocking (or other circumstances), nVidia's implementation of this feature tends to be a bit more sensitive than that found on ATI cards.

It's extremely rare to see artifacts or visual imperfections on a current or previous generation nVidia card. This is because the video core will manually slow itself down before a state stressful enough to cause video artifacts is reached. As readers might imagine, this feature makes determining the maximum overclock attainable by an nVidia card more frustrating than it otherwise would be.

When using the Coolbits hack to overclock an nVidia videocard, there is no indication that this throttling has been activated, so the only way to tell if you've pushed the card beyond its temperature limits is by noticing a decrease in benchmarking scores. If at x MHz the benchmark score increases as normal, but at x+5MHz it suddenly drops several hundred points, the thermal throttling has just kicked in. The frustration really sets in when trying to determine the precise point that the feature activates. Since the throttling is heat-triggered, it won't necessarily be the same value every time.


Best Practices for Overclocking an nVidia Card

To fully exploit an nVidia card's overclocking potential, you should follow this procedure:

1. Using the set of instructions above, enable overclocking on the nVidia videocard.

2. Increase the videocard's core speed only (do not raise the memory speed yet) by 3-5MHz increments, benchmarking at each increment and recording the score. Look for 'snow' (small white particles appearing intermittently) during each benchmark run as a sign the core's maximum speed has been reached. When you see snow, the benchmark refuses to complete, or when the benchmark score mysteriously decreases, the core has been pushed too far.

3. Power down the system for a few seconds to allow the card to cool, then reboot and return the card to its previous fastest 'safe' settings. Increase core speed from here in 1MHz increments until snow appears, the benchmark refuses to complete or the benchmark score decreases. The fastest stable score here is the nVidia cards maximum core speed. Note that due to nVidia's sensitive thermal throttling, the maximum core speed reachable with 5xxx or 6xxx series cards may vary with external conditions. With nVidia cores, it's usually best to 'ballpark' the figure slightly, backing off a few MHz to ensure that throttling does not occur. Don't forget to make a note of the maximum core speed and return the card to its default settings.

4. Following the same procedure as steps 2 and 3 above, increase the card's memory speed in 5-10MHz intervals, leaving the core speed at stock. This time, look out for 'artifacting' while running the benchmark. 3D artifacts will often manifest as jagged lines or flashing objects appearing briefly at certain points of the benchmark. Though thermal throttling should not be an issue when raising the memory speed, keep an eye out for decreasing benchmark scores anyhow. Once problems manifest themselves, return to the highest 'safe' memory speed and increase it in 1MHz increments until the memory's maximum speed is determined.

5. Now for the real test. Raise both the core and memory speed to the maximum values determined in steps 3 and 4, then run the benchmark. If snow, artifacts or problems running the benchmark occur, back both the core and memory up 1-2MHz then try again until the problems clear up. Once the card is running the benchmark stably, record the settings, reboot and start trying out some favourite games. If these appear to run ok, your nVidia video card's maximum overclock has been determined!

Due to nVidia's sensitive thermal throttling mechanism, it's also a good idea to reboot, back the core speed up about 10-20MHz from your maximum value then benchmark the card again and compare the scores. This will make sure that the thermal throttling has not triggered.
 
Power Strip

Power Strip is another great overcloking tool that I wanted to add to the list.

You can get it here!

PowerStrip provides advanced, multi-monitor, programmable hardware support to a wide range of graphics cards - from the venerable Matrox Millennium I to the latest ATI X850 and NVidia SLI solutions.


It is in fact the only program of its type to support multiple graphics cards from multiple chipset vendors, simultaneously, under every Windows operating system from Windows 95 to the x64-bit edition of XP. A simple menu that pops up from the system tray provides access to some 500 controls over your display hardware, including sophisticated color correction tools, period level adjustments over screen geometry, and driver independent clock controls. A powerful application profiler can detect when programs are launched and respond by activating specific display settings, gamma adjustments, performance switches and even clock speeds - returning everything to normal when the program closes. In-game gamma hotkeys let you light up the darkest hallways during game play, and hardware control over refresh rates - with floating point precision - ensure you're never stuck at just 60Hz no matter what OS you're using. A quick setup wizard gets you up and running with minimal fuss, extensive context-sensitive help is available for all controls, and live updates are supported to ensure you're always running the latest release. Finally, an assortment of system and productivity tools - among them, extensive diagnostics, AGP device configuration, desktop icon management, a system idle thread, Windows resource monitoring, physical memory optimization, an on-screen display, and the most advanced monitor support in the industry.

One great thing about PowerStrip is that you don't need to test your newly set clock in order to keep them. All you do is set the clocks and your done, so this way you are not limited to certain frequencies like with other two tools that I listed above.
 
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After you install the PowerStrip it should show up on the quick start menu, if not go to the start menu itself and click on the PowerStrip icon and now it should be there (quick start menu). Right click on the icon and do the following:



After that, raise your clocks as shown in the image bellow and you'r set.




I hope this guide helped some of you guys.

Cheers :beer:
 
This is exactly how I went about OC'ing my card, just prior to this guide. Reading through it I can say it's SPOT-ON and even if you're a newbie to video card overclocking this should be a sinch.

One thing to keep close eye on, like RedDragon said, are your temps. The stock heatsink on your graphics card was not meant to cool a card that runs at a higher clock. You may consider investing in a good GPU cooler which may or MAY NOT further the OC limits of your card--but it will help increase the life of your card, keeping the parts cooler and closer to the temps on a non-overclocked card. I can personally recommend the Zalman coolers and their performance are excellent (and they look cool!)
 
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Wow...amazing sticky man....

BFG 6800GT here, and have been looking for something like this to help me out!

:clap: :clap:

PS: ??? 3DMark 2001SE or 3DMark05 ??? What's the diff?? 4 years is A LOT of time in the computer world :p
 
SlipViper said:
Wow...amazing sticky man....

BFG 6800GT here, and have been looking for something like this to help me out!

:clap: :clap:

PS: ??? 3DMark 2001SE or 3DMark05 ??? What's the diff?? 4 years is A LOT of time in the computer world :p

Limitation, limitation, limitation...
 
RedDragonXXX said:
Limitation, limitation, limitation...
What?? o_O

I kinda meant which one is better/more accurate/more updated. I just haven't gotten into a lot of benchmarking, but from what I read in Mags and Online, there are significant differences between all of the utilities.
 
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For your video card 05 would be the best because it will stress it the most since 01 can't take full advantage of it. That's what I meant by limitation, sorry for the confusion :shrug:
 
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nice guide.

Ok i have a problem here with my evga 6800
i found out it cannot unlock 16/6 (when system restarts, after the xp load screen the screen goes blank)
so my question is, since it cannot unlock will my overall OC on it be lower?
 
calcal said:
nice guide.

Ok i have a problem here with my evga 6800
i found out it cannot unlock 16/6 (when system restarts, after the xp load screen the screen goes blank)
so my question is, since it cannot unlock will my overall OC on it be lower?

Did you flash the BIOS to up the GPU Vcore?
 
hrmm looks complicated

so if i flash to GT bios i can definetly get 16 pieps and 6 vertex?
 
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