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Read B4 going PhysX Crazy

Discussion in 'NVIDIA' started by wolf2009, Aug 12, 2008.

  1. wolf2009 Guest

    This is a must read for everyone intending to play with PhysX. This will solve a lot of your questions and problems that you are going to have.

    NVIDIA's GeForce PhysX implementation

    NVIDIA has created three sets of circumstances on how you can choose to use your PhysX setup from within the PhysX driver, let's have a look:


    • Standard - one GPU renders both Graphics + PhysX (not ideal as you'll need a lot of GPU horsepower).
    • SLI mode - have two GPUs render both Graphics + PhysX (SLI motherboard required)
    • Multi-GPU mode - GPU1 renders Graphics and GPU2 renders PhysX (SLI motherboard not required)

    Below is an example pic of
    [​IMG]

    Most IMPORTANT

    Now there's a thing you will need to be aware of in the Multi GPU mode, it's actually a Vista limitation but a second monitor must be attached to enable PhysX running on the second GeForce GPU. You must extend your Windows Vista desktop onto that monitor.

    To bypass that issue, most monitors have a standard VGA and a DVI connector, right? Just use both. This limitation is related to the Windows Vista display driver model (WDDM). This limitation does not exist in Windows XP. In NVIDIA's upcoming drivers, they will be offering a workaround to improve the experience for Windows Vista users.

    In other words you do not need to have 2 monitors in XP, while in Vista you need 2 connections or you can bypass that with above trick.

    With a single card or two cards in SLI mode you will not have this problem.


    Please Leave a Thanks !

    Taken from here
    Last edited by a moderator: Aug 12, 2008
  2. wolf2009 Guest

    [​IMG]
  3. btarunr

    btarunr Editor & Senior Moderator Staff Member

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    Here's a trick: Use a DVI - DSub coverter dongle.

    The dongle routes back a ground power signal to the DVI even when there's no display connected to the D Sub. In essence you're fooling the system that there is a monitor connected. People use this to start systems for diagnostic purposes when monitor isn't needed (study beep codes / diagnostic LED's), to evade the BIOS halt that occurs in --some-- systems where it beeps for bad VGA connection if a monitor isn't connected. I'm not sure it works in this case though, the OS won't find a monitor in its device list.
    lemonadesoda and EnergyFX say thanks.
  4. pbmaster

    pbmaster New Member

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    So in order to use multi GPU mode do I need Vista?
    If my friend can't get his PC going with the 8800 GTS (G80) I gave him he's going to give it back...I'd like to give this a try.
  5. AddSub

    AddSub

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    btarunr, interesting solution. All my Trinitron monitors have dual switchable inputs and I got plenty of cabling, so I got it covered.

    Have nVidia or Microsoft announced a fix for this Vista issue, since I assume this was not intended to work like this by design?

    Also, has anyone done any Vista vs. XP comparisons yet? I assume there will be a performance penalty under Vista, just how big is the question.
  6. newtekie1

    newtekie1 Semi-Retired Folder

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    You don't have to have a second monitor attached. You can extend your desktop without a second physical monitor attached.
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  7. Flak New Member

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    would this work with HD4850 as the gpu and an 8800gts as the physx?
  8. newtekie1

    newtekie1 Semi-Retired Folder

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    Yes, that would work.

    Edit: It would only work in XP. Vista does not allow this.
    Last edited: Aug 12, 2008
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  9. wolf2009 Guest

    no it dont think so . The physX drivers come through Nvidia Control Panel .

    I may be wrong though.
  10. alexp999

    alexp999 Staff

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  11. newtekie1

    newtekie1 Semi-Retired Folder

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    And why wouldn't it work?

    Yes, the 8400GS should work, and your setup should accept it just fine. I believe the 8400GS is actually a little weaker than a normal PhysX card, mainly due to the 64-bit bus and slower memory. However, it shouldn't affect performance that much.
    alexp999 says thanks.
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  12. Chewy

    Chewy New Member

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    Pretty sweet stuff! hopefully it really pays off! maybe I'll get a 8600gts for physics?

    and Newtechie it might not work because its in the Geforce program, doubt they support Ati cards. but heh it might work :p
  13. wolf2009 Guest

    How will you install ATI and NVIDIA Drivers at the same time ?
  14. alexp999

    alexp999 Staff

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    just to check, this will only effect games which use physx right? I.e crysis is unaffected, but UT3, GRAW, etc will benefit? And you will in theory get better results with graphics cus its not doing physx on the main gpu..?

    :toast:
  15. newtekie1

    newtekie1 Semi-Retired Folder

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    It is pretty simple actually.

    Step 1. Install ATi Drivers
    Step 2. Install nVidia Driver

    Yes it really is that easy.

    Edit: This works in XP. It will not work in Vista.

    Correct, it will only affect games which use PhysX. As for better results, that depends. With the GTX260/GTX280, there is a dedicated spot on the die for CUDA apps, so graphical performance will be unaffected on those GPUs when PhysX is enabled. On lower cards, a portion of the Shader power is used, so graphical performance will suffer. In both cases, the framerate will go down anyway, as there is simply more stuff(particles, smoke, etc) to render, so there is a higher graphical load caused by the increased particle count.
    Last edited: Aug 12, 2008
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  16. alexp999

    alexp999 Staff

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    So getting an extra card wont actually affect performance on my setup cus the GTX260 already has its on bit for physx that doesnt affect graphical performance?
    I may as well keep the money, cus the 8400GS wont actually improve anything...?
    That what your saying?

    Thanks.
  17. wolf2009 Guest

    I'm not sure, I haven't read that anywhere.
  18. alexp999

    alexp999 Staff

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    I'm confused too, cus then surely nvidia would have made a big fuss that their GTX200 series has a built in Physx processor (effectively). :confused::confused::confused:

    Anyone on here test out performance in physx games with a GTx200 series and another nvidia card for the physx...?
  19. btarunr

    btarunr Editor & Senior Moderator Staff Member

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    You can. There's nothing that prevents you from. They're detected by the OS as two display adapters, with either of them becoming primary (head 0). Haven't you come across systems where people used crappy PCI VGA cards on systems with onboard video, so as to add more display heads without having many AGP slots? it's the same. So you install both, the GeForce PhysX driver, make it render PhysX, voila! your GeForce card turned into a physics card a-la Ageia PhysX card.
  20. FreedomEclipse

    FreedomEclipse ~Technological Technocrat~

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    Damn it - that means i will need to start using my old X1800XT as my main G.card & running my 8800GTS as a physX engine - sod that. I was looking forward to this but after reading i dont think this is optimised for non multiple G.cards much but thats kinda understandable.
  21. btarunr

    btarunr Editor & Senior Moderator Staff Member

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    Why would you do that :confused: the 8800 GTS eats X1800 without leaving bones (even while doing graphics + physics)
  22. wolf2009 Guest

    Ya, 2nd that . LOL ! :eek:
  23. Bytor

    Bytor New Member

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    I have a Asus P1 PhysX card installed on my DFI/Intel rig with a Visiontek 3870. I down loaded the Nvidia drivers for the PhysX card and it works great.

    Would I be able to use in game PhysX with this setup?

    The games that came with the PhysX card work fine on that rig..
  24. wolf2009 Guest

    I dont see why not, since its a PhysX card and it runs with PhysX drivers .

    Even the drivers have an option of selecting "Geforce PhysX" or "Ageia PhysX" . So select Ageia PhysX and it will work just fine .
  25. Chomes New Member

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    I have download the drivers from the powerpack, however I can't enable GeForce Phsyx. The options it's disabled. What can it be?

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