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6870 CROSSFIRE questions

post #1 of 6
Thread Starter 
i just bought this card after my 4890 died like 2 weeks ago, it was on sale

http://www.newegg.com/Product/Product.aspx?Item=N82E16814150521


Im saving up around $6-700 to get an 1155 PC by the summer, I was planning on getting ssd, cpu mobo ram and psu, and keep my existing harddrives and probably add a second 6870.

question 1: if i want to crossfire do i need to buy the same EXACT model twice, or can they be slightly different

question 2: I know that even though its 2 cards, I will still only have 1 gb vram since they would be the 1 gb versions. I was wondering if I got a 2gb card as my second card and put that one in the main pcie slot, as in ill have a 2gb card in the x16 slot and a 1gb in the x8, would I get the benefits of having 2gb vram?

thanks in advance
post #2 of 6
yes, your total memory will increased as you add more card.

no need to be exact twin, but it should use same platform. (barts should be crossed with barts)
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post #3 of 6
1) Any 6870 will be fine. The cards will default to the slowest speeds of the two cards

2) No you will get the lowest amount of VRAM of the cards. So in your case you would only get 1GB even if you get the 2GB card
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The Syndicate
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post #4 of 6

 

Quote:

 question 1: if i want to crossfire do i need to buy the same EXACT model twice, or can they be slightly different

question 2: I know that even though its 2 cards, I will still only have 1 gb vram since they would be the 1 gb versions. I was wondering if I got a 2gb card as my second card and put that one in the main pcie slot, as in ill have a 2gb card in the x16 slot and a 1gb in the x8, would I get the benefits of having 2gb vram?
 

 

1. 6870 can crossfire with 6850 of any brands and clocks speed.

 

2. No benefits of 2GB when crossfire with 1GB. Effective is 1GB.

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ケンジ
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post #5 of 6

you got a 1GB so if you get a 2GB you still only have 1GB. I would just get the same card IMO. I am the type of person who has to have matching cards.

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post #6 of 6
Only problem with having non-matching cards is one will probably overclock worse.
Thats the case Im in with my 6850s.

The old card from release date of 6850 does 1100mhz where the new one revision 1.2 only does 1055mhz because it doesnt have as much voltage control.
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