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HD4850 + HD4770 mix crossfire?


JBX

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Hi, im new to the forum. I currently owned a HD4850 on a M4A78-E board with crossfire capabilities. The recently released HD4770 really impressed me in terms of performance / price ratio. The question is can the HD4770 crossfire with my HD4850? And what is the difference performance wise between a pair of HD4850 & a pair of HD4770 in crossfire? Thanks in advance

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Hi, im new to the forum. I currently owned a HD4850 on a M4A78-E board with crossfire capabilities. The recently released HD4770 really impressed me in terms of performance / price ratio. The question is can the HD4770 crossfire with my HD4850? And what is the difference performance wise between a pair of HD4850 & a pair of HD4770 in crossfire? Thanks in advance

No, you cant do that. You can only crossfire the same gpu. 2 4850's will be about 10 fps or more faster than 2 4770's

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Thanks for the answer, i guess i'll be getting another HD4850 & crossfire my system. A little off topic but can a 500W PSU support a 4850 crossfire?

 

Here is my desktop current specs.

unlocked 4-core X3 720BE @ 3.68Ghz, 1.5125V, 230x16

4GB Corsair Gaming Series DDR2-800 @ 920Mhz, 1.8V

Asus M4A78-E mobo

LG 22x DVD-writer

Seagate Baraccuda 7200.12 500GB HDD

5 x Cooler Master 120mm fan rated 4.2W each

2 x Cooler Master 140mm fan

Sapphire HD4850 512mb DDR3

 

Any advice appreciated thanks

Edited by JBX

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I thought you could Crossfire 2 different ATI cards. It would just cause both cards to operate at the slowest card's specifications...

 

If the 500W PSU came with the case, it may support dual 4850s, but I would upgrade when you have the money. It can probably support them for a while, but upgrade the PSU once you have money after buying the second card.

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I vote on just getting the 4850, since you'd be basically running two "4770s" since your 4850 will downclock to the 4770 and there is no guarantee the 4770 will overclock up to the 4850. It'd be a safer investment of the two to just get another 4850 or sell the one you have and get a better single card.

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I thought you could Crossfire 2 different ATI cards. It would just cause both cards to operate at the slowest card's specifications...

 

If the 500W PSU came with the case, it may support dual 4850s, but I would upgrade when you have the money. It can probably support them for a while, but upgrade the PSU once you have money after buying the second card.

 

My PSU is a Silverstone Strider 500W

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I vote on just getting the 4850, since you'd be basically running two "4770s" since your 4850 will downclock to the 4770 and there is no guarantee the 4770 will overclock up to the 4850. It'd be a safer investment of the two to just get another 4850 or sell the one you have and get a better single card.

 

I've heard that HD4770 is a good overclocker, but question is what about RAM clock speed? 4770 runs GDDR5 while 4850 runs GDDR3, as for core clock 4770 runs 750Mhz while 4850 runs 625Mhz. Will the 4770 downclock to 625Mhz? There is also the issue of bandwidth, 4770 only has 128-bit while 4850 has 256-bit, will this cause alot of issues? I've read an article about mix crossfire between a 4850 & 4870 the results were that they are slightly better than 4850 crossfire. Maybe a 4770 & 4850 setup will be slightly better than 4770 crossfire? Any input?

 

Thanks for all your answers guys.

Edited by JBX

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I've heard that HD4770 is a good overclocker, but question is what about RAM clock speed? 4770 runs GDDR5 while 4850 runs GDDR3, as for core clock 4770 runs 750Mhz while 4850 runs 625Mhz. Will the 4770 downclock to 625Mhz? There is also the issue of bandwidth, 4770 only has 128-bit while 4850 has 256-bit, will this cause alot of issues? I've read an article about mix crossfire between a 4850 & 4870 the results were that they are slightly better than 4850 crossfire. Maybe a 4770 & 4850 setup will be slightly better than 4770 crossfire? Any input?

 

Thanks for all your answers guys.

I forgot there were so many big differences like that, I'd stick with the same card if possible or the better option would be to just get a better single card like 4870/4890 or 260/275 don't crossfire/sli unless it's the last option available

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