What are the role of a CPU and GPU in relation to gaming

Discussion in 'Hardware Q&A' started by savagex, Mar 26, 2012.

  1. savagex

    savagex savage Computing...

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    Hi Guys,

    Having this question for a long time now. Tried to google but to no avail.

    While browsing through the threads, people have suggested CPUs which are good for gaming. But isn't the GPU responsible for rendering the graphics ?

    What exactly are the role of a CPU and GPU in relation to gaming ?
    It will be very good if somebody can post a technical writeup or any link for this.

    Highly appreciated !!
     
  2. RiGOD

    RiGOD SoLa BeLLaToR...

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    Strict buying advice here mate.

    AFAIK GPU plays the most crucial part in gaming at higher resolutions (Full HD or greater). As the resolution is lowered the load on the GPU is eased and it might become CPU intensive. And the main thing is that you CPU should not bee too outdated or else it'll bottleneck the performance of your GPU. Correct me if I'm wrong.
     
  3. whitestar_999

    whitestar_999 Super Moderator Staff Member

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  4. OP
    savagex

    savagex savage Computing...

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    Sorry guys.... Wrong section.... :(
    Mods please move it to the right section.

    I have a Phenom II X2 550 BE. Would it be able to deliver good HD gaming experience coupled with a good graphics card and 970 chipset based mobo ?

    @whitestar_999 : Also can you give me a more detailed explanation ?
     
    Last edited: Mar 26, 2012
  5. topgear

    topgear Fast 'N' Furious Staff Member

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    ^^ with a good GPU your CPU is capable enough to handle all of the latest games .. if you need extra performance boost try unlocking the cpu into a quad core ;-)
     
  6. ico

    ico .</br><img src="http://i.imgur.com/XoY1dbu.jpg"/>< Staff Member

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    I'll explain in a very simple language. :)

    Theoritically, a CPU has to be fast enough to feed the insturctions to the GPU.

    Small hypothetical examples.

    Example #1

    You pair HD 6570 with a Pentium 4. You get 40 FPS in a game. Then you pair HD 6850 with a Pentium 4. You still get ~40 FPS in a game.

    This was an example of "CPU bottleneck" - in which CPU was not fast enough to run the game and feed instructions to the GPU. So if using a Pentium 4, then getting anything above HD 6570 will give you zero benefit in games.

    Example #2

    Guy X purchased Phenom II X4 965 BE (Rs. 7500), a motherboard (Rs. 6000) and HD 6970 (Rs. 21000). Total cost = Rs. 34,500.

    Guy Y purchased Core i7-930 (Rs. 13000), a motherboard (Rs. 10000) and HD 6850 (Rs. 11000). Total cost = Rs. 34,000.

    Core i7-930 is the faster processor than Phenom II X4 965 BE. But Guy X's computer will be faster than Guy Y's computer in games.

    Reason? Guy X has a much much faster GPU. And Phenom II X4 965 BE might be quite a bit slower than Core i7-930, but it is in no way a "bottleneck" and still powerful enough to feed a HD 6970.

    -------------------------------------

    Example #3

    One more example. X4 965 + HD 6970 vs i7-930 + HD 6970 when playing games at a very low resolution of 1024x768.

    So, in this case we are playing on a very low resolution. Pairing both the CPUs with the same GPU.

    You'll expect i7-930 to win in this case because it is the faster CPU afterall. In low resolutions, you are not "working" up the GPU by much. GPU load will be low and CPU speed will affect the winner.

    Less resolution = CPU bound. But no one games at these resolutions anymore. 1920x1080 performance is what everyone should look at.

    Example #4

    X4 965 + HD 6970 vs i7-930 + HD 6970 when playing games at 1920x1080. You could say this is a high resolution.

    In this case, don't expect the gap between both the configs to be much. Both will perform similarly. May be the i7-930 config will win, but not by much.

    Both processors are avoiding the bottleneck and 1920x1080 resolution is more GPU intensive. GPU load will be high.

    More resolution = GPU bound.

    Example #5 - multi-GPU and multiple displays.

    a)

    Let's use HD 6990 + HD 6970 "Trifire"....that's three GPUs. Resolution = 5760x1080. Three 1920x1080 displays. Processors we will use are FX-8150 vs i5-2500k.

    Resolution is very very high - both CPU and GPU will get worked. In this case you'll see that i5-2500k will win if the game is CPU intensive. Because FX-8150 is the slower processor.

    Multi-monitor resolutoin gaming = the type of game will make a huge difference here. GPU intensive obviously, but if the game is CPU intensive, CPU performance will make a difference.

    b)

    HardOCP had tested GTX 580 2-way SLI and 3-way SLI on i5-2500k and FX-8150 respectively. Their result:
    AMD FX-8150 Multi-GPU Gameplay Performance Review

    -------------------------------------

    Now we have games. Few games are single-threaded and few are multi-threaded. Majority of games now use 2 threads at the moment. But from 2010 we are seeing that most games are utilising 4 threads.

    Starcraft 2 - for example. Single-threaded and CPU intensive. Core i3-2100 (2 cores/4 threads) will win against Phenom II X4 965 BE (4 cores/4 threads) regardless of the GPU you use. SC2 is very CPU intensive - almost like a low-resolution game scaled up.

    GTA IV - very CPU intensive game. The more cores you add, the better it is. X4 965 BE being a quad-core will win against i3-2100 (dual hyperthreaded cores). Faster GPU made no difference for this game. All it needed was 4 cores and overclocking to run properly when it was released. Nothing less.

    Resident Evil 5 - can make use of upto 8 threads. FX-8150 (8 cores) might have a chance against i5-2500k (4 cores) here.

    Battlefield 3 - an example of dual-threaded GPU intensive game. No matter how many cores and which processor you throw at it (Phenom II, FX or Sandy Bridge) - it used only 2 threads and performed equally. The GPU solely defined the performance in this game.

    Civilization V - multi-threaded, very CPU intensive and very GPU intensive.

    -------------------------------------

    Nutshell: Gaming performance = mixing and matching of many things. There are aberrations to what I wrote above - but it is still a fair gist overall to the best of my knowledge. :)

    Regarding your Phenom II X2 550 BE. It alongwith Core 2 Duo E74xx/E85xx is fine for gaming at least for the time being. 550 BE overclocks nicely as well. If you feel it is slow, overclock it. It will not be fine from next year or so. Games are starting to utilise 4 threads now. Pretty much the reason why Athlon II X4 gets more recommendation than this in TDF.
     
  7. OP
    savagex

    savagex savage Computing...

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    Thanks ico for this worderful, exhaustive explanation. :)
    This clears a lot of air.

    I will wait for the AMD piledriver CPUs to come out before upgrading this CPU. And yea hopefully can unlock the 550 BE to a quad core.
    Does anybody know a 970 chipset based mobo which can unlock this CPU (ACC) ?
     
  8. ico

    ico .</br><img src="http://i.imgur.com/XoY1dbu.jpg"/>< Staff Member

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    ^^ Unlocking isn't guaranteed.
     
    krishnandu.sarkar likes this.
  9. amruth kiran

    amruth kiran food-football-g(f)aming?!

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    DAMN ico. you really put a lot of effort in that explanation. kinda cleared a lot i my head too.!! thanks!!
     
  10. krishnandu.sarkar

    krishnandu.sarkar Simply a DIGITian Staff Member

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    Thanks ico :D

    It made many of my concepts much clear now :D
     
  11. whitestar_999

    whitestar_999 Super Moderator Staff Member

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    very good & detailed explanation ico.along with VRM this topic too deserves a sticky in my opinion in gaming/graphics section.
     
  12. OP
    savagex

    savagex savage Computing...

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    Yea right... it isnt guaranteed.
    but are there any 970 chipset based mobos with ACC so that i can try ?
     
  13. gopi_vbboy

    gopi_vbboy New Member

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    ya i think ico post needs to be put in some existing/new sticky thread in gfx section..good expl...
     
  14. topgear

    topgear Fast 'N' Furious Staff Member

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    get Gigabyte GA-970A-UD3 but don't fool around with the ACC option - it's not there anymore ( on any 9xx series mobo ) instead search for a new option called CPU Core Unlocker ;-)
     

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