If I don't enable RTX features with an RTX Super card, are those parts of the GPU idle/unused?

Discussion in 'Videocards - NVIDIA GeForce' started by BlindBison, Jan 11, 2020.

  1. BlindBison

    BlindBison Ancient Guru

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    Or, are those RT cores put to use on other sorts of tasks?

    I recently ended up with a 2080 Super since my current PC broke while under warranty, but I find in Battlefield V for example that the difference in graphical fidelity isn't all that huge to my eye -- but the framerate cost seems quite significant.

    If I don't have Raytracing or DLSS enabled at all, does that mean my GPU has parts of it that are not being utilized at all and are just sitting idle?

    It would seem to me that enabling RTX at its lowest available setting might be the way to go just to ensure you're actually making use of the GPUs full capabilities, but I really am unsure how it works.

    Thanks for your time, I appreciate it
     
  2. uKER

    uKER Master Guru

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    Yes, the RT and Tensor cores only do those tasks. If you disable those functions, that hardware is left unused.
     
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  3. gerardfraser

    gerardfraser Guest

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    Nvidia put a timer on those tensor cores,if they go unused for a certain amount of time the self destruct.So be careful on .
    Code Name-Mission Impossible core
     
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  4. Shakey_Jake33

    Shakey_Jake33 Guest

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    N00b question - what causes the significant hit to framerates if ray tracing is carried out on the dedicated RT cores?
     
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  5. Ital

    Ital Master Guru

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    Here's a simple analogy:

    Let's say a chef can make a dish in 30 minutes. However, to make it a really special dish, he needs to add a special sauce (RT) which requires an additional 120 minutes to make. Since the sauce has to made fresh every time and requires constant stirring, the chef can't do anything else while making the sauce. That means total time for the chef to make the special dish is 120 + 30 = 150 minutes.

    Customers complain that it's too long, so he hires an assistant (RT core) who can make the sauce in only 60 minutes since he's really good at making sauces. Does that mean the customer can get the special dish in 30 minutes? Nope, it still takes 60 minutes for the specialist to make the sauce, so the chef has to wait until the sauce is ready to serve the special dish to the customer.

    So, without the sauce it only takes 30 minutes, but with the sauce it takes 60 minutes with the assistant's help. Without the dedicated assistant, it takes 150 minutes.

    Of course, if the assistant can create the sauce in only 30 minutes or less, then dish can be served in 30 minutes. Unfortunately, the RT cores in the current RTX series aren't that fast yet, so everything else in the GPU has to wait on the RT cores to produce that "special sauce".

    And to answer OP, if the customer orders a dish that doesn't require the special sauce, then the assistant just sits around doing nothing since all he can do is make the special sauce and can't help the chef with anything else.
     
    Last edited: Jan 12, 2020
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  6. elaganza

    elaganza Master Guru

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    but on other hand if you activate Ray tracing in supported games you will see huge decrease. if rt cores work on rays rendering only so why is that?
     
  7. mbk1969

    mbk1969 Ancient Guru

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    Do not believe in self destruction theory. Actually NVIDIA will do cryptocurrency mining.
     
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  8. GREGIX

    GREGIX Master Guru

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    Because. It. Just. Works.
    This way....
    Simple answer is, this tech and cards are rushed to be ahead of AMD, as they applied patents for ray tracing in 2017? Or earlier. With consoles in mind, as AMD delivers GFX and CPU for them. Nvidia panicked a little and released RTX a bit too early, and product while doesn't suck totally, is nowhere where expectations were...it is fast, but its huge, costly to assemble and in total eye candy features killing its performance.
     
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  9. Astyanax

    Astyanax Ancient Guru

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    Tensor cores are leveraged as 16bit floats and RT cores are utilised by the cache as an optimizer.

    Raytracing is not carried out on the dedicated RT cores, it is an overall function of the RTX SM rendering pipeline.

    RT (BVH units) performs the task of finding out if a ray hits, intersects or misses an object and passes the information on to the traditional shader engine to render the scene information.


    The fixed function RT cores are faster than multi-function programmable shaders and you can only make them faster with clock speed increases

    Neither RT core count, or clock speed is the source of the framerate decrease.

    Gains for RT performance between each tier of RTX card are due to increases of SM's, which inturn increase how many traditional shaders are present on the device, more so than the fact you gain an extra RT core for each additional SM.

    Pay heed to the fact that RTX technology was announced originally for Volta GV100 parts, including the Titan V, and this performs faster than Pascal without the presence of the RT cores attached to each SM.
     
    Last edited: Jan 12, 2020
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  10. BlindBison

    BlindBison Ancient Guru

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    @Astyanax

    > “Tensor cores are leveraged as 16bit floats and RT cores are utilised by the cache as an optimizer.”

    Wait, so those parts of the GPU actually DO do something if you’re not using them for RTX? Correct me if I’m misunderstanding your meaning, thanks.
     

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