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4870 crossfire with 4850 questions and results.

Discussion in 'AMD / ATI' started by TheMailMan78, Apr 21, 2009.

  1. TheMailMan78

    TheMailMan78 Banstick Dummy

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    I am about to get in a 4870 "Dark Knight" 1GB to crossfire with my Asus 4850 "Top" 512. What kind of performance increase could I be looking at? Game and benchmark. I know my CPU is a bottleneck right now but I plan on remedying that soon ;)

    Once I get it in Ill post my benches. :toast:
  2. Binge

    Binge Overclocking Surrealism

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    Fantastic man. I've heard if your 4850's memory can overclock well then your performance boost will be pretty good :)
  3. TRIPTEX_CAN

    TRIPTEX_CAN

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    You should get a nice performance boost in games that dont really need more than 512mb framebuffer but in games like Crysis and Stalker:CS you might notice the games not playing as smooth despite being a higher framerate.
  4. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Well its better than what I had. I was running duel 4850s.
  5. TRIPTEX_CAN

    TRIPTEX_CAN

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    Should be better.. although I dont think it will be all that much faster. The "extra" 512mb on the 4870 will go completely unused.
  6. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Why?
  7. Binge

    Binge Overclocking Surrealism

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    the way x-fire works is it can only use as much memory on each card as the card with the lowest amount. -eyes spinning-
  8. theorw

    theorw New Member

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    Now for my case i found a MSI 4850 for 64 euros in stock with 3 years warranty
    Should i buy it and crossfire it?????Isnt it a bargain???
  9. afw

    afw New Member

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    hey i once read a review that the faster xfire card will clock down to the lower speed card ... so basically only a 4850 xfire performance can be expected... :( ... but i'm not sure wat'll happen if u clock ur 4850 to same as 4870 ..
  10. theorw

    theorw New Member

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    The clocks MUST be the same so and they MUST be the clocks of the lower clocked core!
    So u clcock the 4850 @ 750 and u r fine!!!
    And the ram as much as u can!!!
  11. afw

    afw New Member

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  12. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Is it the same with speed? I mean the 4870 has DDR5 and the 4850 DDR3.
  13. theorw

    theorw New Member

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    YES IT IS!
  14. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Crap. Ill have to do some serious OCing then.
  15. theorw

    theorw New Member

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    Well if u clock it @2400 i think u should be fine!The added GPU power should do most of the work i think!!!
  16. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Well the 4870 is DDR5 at 900Mhz where the 4850 is DDR3 at 993. Ram isnt the issue. Its the core speed. I need to get the 4850 up from 680 to 750 like the 4870 is.
  17. erocker

    erocker Super Moderator Staff Member

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    No, RAM speed and size is going to be your issue. 1/2 of the memory on the 4870 won't get used and it will only run as fast as the GDDR3 on the 4850. Other than core speed there will be no difference with the 4870 that replaced the 4850.
  18. TheMailMan78

    TheMailMan78 Banstick Dummy

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    I just pwned myself then. Is it even possible to come close to the DDR5 clocks?
  19. erocker

    erocker Super Moderator Staff Member

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    Vmod the 4850? Sell the 4850 and get yourself another 1gb 4870. The bandwith of GDDR5 is just so much more than GDDR3 it's ridiculous! If the resolution and stuff you use can benefit from 1gb of Vram than your best bet is to just use the 4870 for now.
  20. theorw

    theorw New Member

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    The res he plays on doent need another 4870.Or the 1 gb of frame buffer either rather than in crysis...
    1 more 4850 should do the job.Just do a llitle pencil mod and u can easily reach the 750 of the 4870!As for the ram no way u can achive gddr5 clocks but u can reach 2400 easily.
  21. TheMailMan78

    TheMailMan78 Banstick Dummy

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    :laugh: I sold my other 4850 to buy the 4870. So until I get another 4870 Ill see no performance increase? Will I see a decrease?

    FYI I never game over 1680x1050.

    <<:nutkick:
  22. Gjohnst4

    Gjohnst4 New Member

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    I think the advice of selling the the other 4850 once you have the money is your best bet. No rush, but once you can afford it, and the extra cash to get another 4870 1 gig card, you wont be throwing away 512 mb of ram. This happened to a buddy of mine a year ago who crossfire a 3870 512mb with a 3850 256mb. He overclocked the 3850 to 3870 speeds, but lost 256mb of ram and took a performance hit.
  23. newtekie1

    newtekie1 Semi-Retired Folder

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    No, you shouldn't see a performance decrease. You might get a slight increase, but it will not be noticeable.
    Crunching for Team TPU More than 25k PPD
  24. TheMailMan78

    TheMailMan78 Banstick Dummy

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    Well thats good. Maybe 10 frames? Ill get another 4870 1gig after I upgrade my CPU.

    Would it be better if I just sold the 4850 now? I mean I cant imagine two 4850s being slower than one 4870.
  25. erocker

    erocker Super Moderator Staff Member

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    x3 720's are getting cheaper and cheaper! I wonder if you'll notice more of a difference with a new CPU? Get the 720!!

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