How to Disable Turbocache

So, I recently bought a Geforce 7300GS PCI-e 256MB video card with Turbocache. I was surprised to see that it didn't really outperform my old 128 MB Geforce 5200FX. Seemed like it was hiccuping under load. After some research, I learned that it might be Turbocache. Unfortunately, there was no apparent way to turn it off... until now :)

I know this (usually) works on Windows XP, but I haven't heard of it working in Vista. Since I don't have (and refuse to own) Vista, I may never figure it out. But, if anyone does, please comment; I'll include it and you'll be famous!

Update 11/01/2007: Thanks to an anonymous commenter, it appears that Vista now controls shared memory for the GPU instead of the video driver (http://www.microsoft.com/whdc/device/display/graphicsmemory.mspx). Not sure I agree with that (in architecture concept, not the comment), but it'd be okay if they at least gave you an option in your Display control panel :\ So, looks like it's time for someone with Vista to go hunting through the registry. Obviously that someone is not me because I'll never own Vista. So, the opportunity to be famous is still out there!


Here's what you need:

• A video card with Turbocache (duh). It pays to get a card with more onboard memory, like 256MB
  
• The latest nVidia drivers. You might already have these. I use Forceware 93.81, but I think the latest stable will work too.
  
  Update 09/1/2007: It seems that the latest and greatest don't do the job. Try these instead.
  
  Update 09/11/2007: These nVidia drviers (162.18) will work. Just make sure you have the latest Rivatuner (2.0.6 at the time of this writing). I've had better results with these drivers than 93.81.
  
  Update 05/17/2008: I just upgraded my drivers to nVidia's new version of driver (175.16). My turbocache is still disabled, and I actually noticed an improvement in performance with the new drivers. I didn't upgrade Rivatuner, although version 2.09 is out as of April 30, 2008.
  
  
• Rivatuner

Now, down to business...

Verify The driver

First, check and/or update your video driver. You've probably already done this, but if you need some help to make sure that you have the right one, do the following:

1. Right-click your desktop and click Properties.
2. Go to the Settings tab.
3. Click the advanced button.
4. Go to the Adapter tab (note the Memory Size under Adapter Information).
   
5. Click on Properties button.
6. Go to the Driver tab.
7. Verify the Driver Date and Driver Version to make sure it's the one you need.
   
8. Close the dialogs.
9. If your Forceware version isn't at least 93.81, then download and install the correct nVidia Driver (link above).
   

Install Rivatuner

Download it from here if you haven't already. No fancy installation options necessary; just install it.

Hey, that was easy, right? Now comes the important part...

Disable Turbocache

1. Open Rivatuner
   
2. Go to the Power Users tab
3. Click on the Open Matched Database button. It's one of the little ones on the bottom.
   
   Update 09/18/2007: Here's some additional information I found (posted on Neowin by BlackShadow) to help you if you get the error: "Riva Tuner cannot find the database for Forceware XX.XX. Do you want to open database for the closest driver version?"
   
   
   If you have driver version 94.24 or above, click 'no'.
   If you have driver version 94.24 or below, click 'yes'.
   
   
   
4. Find and expand the "nVidia Forceware xx.xx w2k System" entry in the list:
   
   
5. Find RMDisableRenderToSysMem and set the value to 1:
   
   
6. Close Rivatuner
7. Reboot the computer

Double-check to see that your card is "normal" and not using system memory anymore. Repeat the "Verify your driver" steps to view the properties of your video card and see if the memory listed is only what's onboard (up to step 4 under Verify The Driver).

All RivaTuner does it set a value in a specific registry key (see more in the comments below). But, I think it's nice having a GUI to wade through stuff like this.

And that should be it!

I noticed a performance gain on my system, probably because it wasn't paging to the system memory. Just one less thing the CPU had to keep track of.

If this makes matters worse for you (which I can't imagine that it would), the just go back in and delete the 1 value for the RMDisableRenderToSysMem entry in Rivatuner, and you'll be back to the way you were.

Comments on success stories, failures, and corrections/alternate steps are always welcome. And, there's no guarantee that this works (for some reason), so if it doesn't work for you, play with it until it does and then let us know what worked for you.

Just remember my standard disclaimer: you did it and it's your fault if it breaks!

Happy tweaking!