I Need Some SLI Decision Help

[mhumm2]

Hello;

I just received a gift of a new video card which is the same model as the one in my computer system. It's a nVidia GeForce 9800GT. Now that I have 2 of them and 2 PCI-E x16 slots, I want to install the card and enable SLI graphics. Well it is apparently more complicated than I first thought. When I installed the card, Kubuntu would boot to a basic x window interface. I've since removed the card and the system is back at the starting point again. I obviously need more information.

I'm currently using nvidia driver 270.41.06 and driving my Dell 2407WFP at the native 1920 x 1200.

What I need is a procedure to set the whole thing up. I know how to install the gfx card, I'm just not sure when; before or after I invoke SLI in the xconf file. Oh btw, since I'm using Kubuntu 11.04, I don't have a graphics config file by default although I can create one, so there's another question: Should I have a graphics config file?

After reading nvidias site and a couple other Linux users, I think I want to run in AFR mode. I understand the mode, but if one of the other modes is better or more stable in Linux, I'm open to those inputs too.

Thanks in advance.

[oshunluvr]

Re: I Need Some SLI Decision Help

Section "Screen"
~~~
Option "SLI" "AFR"
~~~
EndSection

[oshunluvr]

Re: I Need Some SLI Decision Help

I don't know why you had a problem initially. I suggest you add the above option to xorg.conf and then try again. If you end up at the terminal again, look at the log file /var/log/Xorg.0.log and see why it's crashing. Could be hardware related too so try the new card by itself before you do too much additional troubleshooting.

[mhumm2]

Re: I Need Some SLI Decision Help

Thanks oshunluvr;

I assume then, that I should create an xorg.conf file. So as for a procedure:

1. Swap my gfx card out with the new card to make sure the new card works.
2. If step 1 passes, create an xorg.conf file with SLI turned off.
3. Power up and boot the computer and see if the original card works with the xorg.conf file. Tweak file as needed.
4. Once step 3 is a "GO," install both cards in SLI config and add: "Option 'SLI' 'AFR'" to the xorg.config file.

Thanks again.

BTW, I just comprehended your moniker. Nice. I live 2 miles from the Gulf of Mexico along the Florida panhandle. They call it the "Red-neck Rivera." Take care.

I'll start today. Thanks again.

[oshunluvr]

Re: I Need Some SLI Decision Help

I concur with your planned steps, but add this:

You'll get the best performance out of your nvidia card(s) is you use an xorg.conf file and add just a few options. Most of the basic stuff is already enabled by default in xfree86 so you only need a couple. Keep in mind my cards are 8800GT's so you will need to research your specific card's chipset to find the best options for you.

Also - install gtkperf to test your performance. GLXGears isn't really a performance tester, it just confirms the GLX is enabled.

Here's my Device Section:

Section "Device"
  Identifier   "Device1"
  Driver     "nvidia"
  VendorName   "NVIDIA Corporation"
  BoardName   "GeForce 8800 GT"
  BusId     "PCI:2:0:0"
  Option     "Coolbits" "1A"
  Option "TripleBuffer" "True"
#        + Enables triple buffering. "Decreases the time an application stalls while waiting for vblank events, but increases latency slightly" (NVIDIA Readme) 
  Option "UseCompositeWrapper" "True"
#        + Enables the X server's composite wrapper instead of the builtin one. 
  Option "BackingStore" "True"
#        + Cache overlayed areas in case they get redisplayed later 
  Option "OnDemandVBlankInterrupts" "True"
#        + only fire VBlank interrupts in modes where they are needed 
EndSection

I suggest you search for some beneficial options for your cards, run gtkperf to get a base line, then add the options in and re-test until you get maximum results. I also over-clock my cards, but they're water cooled so I'm not sure you ought to try that. Also - during the testing phase, make a backup of any working xorg.conf so you can revert. Get familiar with nano (terminal based text editor) for when you're stuck in terminal mode, and finally - you don't have to reboot between edits to test, just use the command sudo service kdm restart You only need to reboot if you install a driver.

BTW: The handle came from being a sailor and scuba diver here in SoCal. We have personalized license plates that have a heart symbol available. So my plate is OSHUN<heart>R. I liked it enough that I user "oshunluvr" for all my social media except Yahoo. Some dirtbag took it before me so there I'm oshunluvr9.

[Detonate]

Re: I Need Some SLI Decision Help

BTW, I just comprehended your moniker. Nice. I live 2 miles from the Gulf of Mexico along the Florida panhandle. They call it the "Red-neck Rivera."

I love that part of Florida. I spent a lot of time in Panama City, Ft. Walton Beach, and Destin in my younger years.

[dequire]

Re: I Need Some SLI Decision Help

BTW, I just comprehended your moniker. Nice. I live 2 miles from the Gulf of Mexico along the Florida panhandle. They call it the "Red-neck Rivera."

I love that part of Florida. I spent a lot of time in Panama City, Ft. Walton Beach, and Destin in my younger years.

I used to live in Orange Park FL and then briefly in Middleburg Heights. Very interesting part of the country to say the least.