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should i run 4850/4830 hybrid?

Discussion in 'AMD / ATI' started by Kona1169, Jun 25, 2010.

  1. Kona1169 New Member

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    so i have a spare 512mb 4830 and was wondering if its worth it to add it with my 1gb 4850

    heres the benches

    Passmark = 4850
    http://img651.imageshack.us/i/49624031.jpg/


    Passmark= 4850 + 4830 CF
    http://img101.imageshack.us/i/97424926.jpg/



    it seems that the single card beats the cf sometimes, i think my mobo goes from x16 single to x8 cf

    Unigine heaven dx11, aniso 4, anti 2X 1920x1080

    4850:
    fps 23.5
    score 591
    min 5.5
    max 45.3

    4850+ 4830CF
    fps 38.7
    score 961
    min 19
    max 77.7

    i only ran once for each of these benches
     
    Last edited: Jun 25, 2010
  2. Hellfire

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    Image link isn't working for me,

    From the info I got at the bottom it seems the Xfire hybrid set-up seems better, in all honesty you will not lose much performance going from x16 to x8.
     
  3. Kona1169 New Member

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    alright the links are fixed. i really wish i had a fan shroud for that 4830. i took it off because i couldnt fit it into my old computer. last night i put my hand in my case and the fan cut my finger of which it bled lol.

    should i maybe overclock the 4830 to the 4850? would it be as simple as matching the mhz and clocks?
     
  4. BrooksyX

    BrooksyX

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    A 4830 should over clock to a 4850 speed very easily. My 4830 reached 950mhz on the core with a pencil volt mod. I ran 2 of those in crossfire for a while. It was a pretty bad ass rig.
     
  5. Kona1169 New Member

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    do i just set the 4830 to 625 gpu and 993 mem (what the 4850 is) from 575 gpu and 900 mem?

    i more want to do it as i think it would be a bit of a bottleneck to have a card running slower no? although one card is 500mb bigger =/
     
  6. Dent1

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    You carry out the overclock as you would normally, you initially only run the 4830 and you gradually push up the memory and GPU clock using software or ATI catalyst and test it for a few days, use stress testing software where necessary, once you've reached the maximum overclock and you are certain its stable you flash the firmware to make it permanent. Then you add the 4850 for crossfire.

    The 4830 and 4850 have very similar performance so even without overclocking it will not bottleneck one another in hybrid.

    If one card has 512MB and the other has 1GB, the 1 GB card will drop down to 512MB of available video memory, so it will be 1 GB total video memory across two cards not 1.5 GBs.
     
  7. brandonwh64

    brandonwh64 Addicted to Bacon and StarCrunches!!!

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    Ygpm :)
     
    Crunching for Team TPU
  8. Kona1169 New Member

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    i read on a post when the 4830 was clock for clock OC that its still 3 percent slower. ive overclocked my 4850 before and i didnt see THAT much of a improvement. maybe 2-3 fps and it would get screen tears lol.

    i ive read that only nvidea downclocks not ati cards? from those results is it worth it to run crossfire? i noticed that on passmark that theres some fps that are lower, dunno why. i also only have 1 ribbon for CF
     
  9. erocker

    erocker Super Moderator Staff Member

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    Actually running a 512mb card with a 1gb card, your bandwidth will be limited to the 512mb card. So you will use 512mb total.
     
  10. Kona1169 New Member

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    wait wouldnt it be a total of 1gb since each card would be using 512mb?
     
  11. slyfox2151

    slyfox2151

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    no, the memory is mirroed to each card.

    so it would be a total of 512mb.
     
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  12. Dent1

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    The 4830 has 640 shader units whereas the 4850 has 800 shader units, so the 4850 will always have a slight advantage even at the same clock speed. But in the majority of the cases the 4850 and 4830 will still perform about the same as one another with or without an OC.


    Where did you hear this? from a respected review or was it hearsay from a "friend". Both Nvidia and ATi leave headroom on their products (i.e. downclocked buses) to allow customers to overclock at their own risk.
     
  13. Kona1169 New Member

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    ive heard it a couple times on a forum. gpuz still shows their both running at their stock clocks and windows shows theirs 1.5gb of vid rams so i dunno.

    ive noticed when i load videos on my browser (youtube and whatnot) i get screen flickers. whats up with that? i have the 10.6 drivers in here if that matters. could it be my powersupply not bringing enough juice?
     
  14. Dent1

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    Its most definitely driver related, make sure the refresh rate is set to your monitors default and you are running your native resolution, apart from that all you can do is downgrade driver versions.
     
  15. Kona1169 New Member

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    okay so it doesnt do it when i have one monitor connected only when im running dual. both are running 60-75hz. any idea what may be causing this? it doesnt do it with one gpu. i have the cf bridge on the inner plug.
     
  16. Mussels

    Mussels Moderprator Staff Member

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    the flicker is normal. its crossfire kicking in for the hardware acceleration in flash these days.

    Video ram is not added up in crossfire, its locked to the lowest card.

    as for the other stuff:

    ATI cards do not downclock/match clocks in crossfire.

    windows shows how much video ram is on the cards AND how much system ram is available for when they run out. its irrelevant, really.


    the problem with one card beating two cards, boils down to one of two things.

    1. The game/app has no crossfire profile in the drivers you're running, so its dropping to one card.

    2. you're CPU limited. it takes more CPU power to feed two cards, so you can get lower performance in situations where you are held back by that.
     
  17. Kona1169 New Member

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    if the game doesnt support cf i guess it will revert back to the 1gb on the 4850? how is the support on crossfire on games anyways these days i remember it used to be supported by little.

    i guess im still better off running cf tho even though it does drop the total memory right? i saw a 10-15 fps increase on the unigen benchmark although i did see a drop on the passmark benchmark on some tests =/
     
  18. Mussels

    Mussels Moderprator Staff Member

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    oddly no, if a game doesnt support crossfire you're still held by the ram limitation of the weakest card.
     

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