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3870 + 3850 in crossfire?

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orph3us

n00b
Joined
Dec 2, 2007
Messages
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Hello, new member here... I just bought a viewtek ati 3870 gpu for $215 off of bestbuy.com :D and I receive it tomorrow. I'm upgrading from an nvidia 7800gt and I have an intel 775 chipset with crossfire capable in 8x 8x mode. First, is this a good upgrade? Second, I want to go crossfire in the next month, will running in 8x mode hurt my performance at all? Third, is it possible to run the 512 mb 3870 with a 256 mb 3850 in crossfire? Will my performance be much worse than if I were to buy a second 512 mb 3870? I figure if I can save some money, I'm only going to be running at 1280x1024 and the second card for crossfire wouldn't need to have 512, but I'm not sure if its even possible to mix the 3870 and the 3850 and if the performance would be much worse than dual 3870's maybe I'll just go for that... thoughts?

oh and thanks for reading/replying :)
 
orph3us said:
Hello, new member here... I just bought a viewtek ati 3870 gpu for $215 off of bestbuy.com :D and I receive it tomorrow. I'm upgrading from an nvidia 7800gt and I have an intel 775 chipset with crossfire capable in 8x 8x mode. First, is this a good upgrade? Second, I want to go crossfire in the next month, will running in 8x mode hurt my performance at all? Third, is it possible to run the 512 mb 3870 with a 256 mb 3850 in crossfire? Will my performance be much worse than if I were to buy a second 512 mb 3870? I figure if I can save some money, I'm only going to be running at 1280x1024 and the second card for crossfire wouldn't need to have 512, but I'm not sure if its even possible to mix the 3870 and the 3850 and if the performance would be much worse than dual 3870's maybe I'll just go for that... thoughts?

oh and thanks for reading/replying :)
Click to expand...

1. Yes, excellent upgrade.
2. No. 8x is fine.
3. Ideally you want to use identical cards for Crossfire. You can use a 3870 with a 3850 and you will see improvements, but not nearly as much as what you would see with two 3870s.
 
Basically you'll get very nearly the same results as if you were running two 3850's...the drivers won't allow the 3870 to access more than 256mb, but at your target resolution it won't be that bad.

The higher clocks on the 3870 will help a *little* bit compared to running two 3850's, but we're talking 1, maybe 2 FPS here, or a hundred or so 3dMark06 points.

But, in games that don't support Crossfire, you'll be better off, since the 3870 does carry more water alone than the 3850.
 
so the drivers won't allow it to access more than 256 with a 3870 and a 3850 in crossfire? but with two 3870's it will use full 512 for both?
Thanks for the replies
 
You could get a HD 3850 512MB. Then you could use the full 512MB. Also the cards run at their own clock speeds so it should be fine. Dunno how much you would save though.
 
what kind of board are you using? the only 775 8/8 crossfire board i know of is the expensive and rare asus blitz.
 
Just get another 3870, very simple and you won't have to think about any performance loss, it'll just be gains. I think it's worth it too. 3870 cf beats the 3850 cf. If you get a 3850 along with your 3870, you'll have an overpriced 3850 cf setup.
 
I am using the asus p5w dh deluxe.. it was expensive but I got a discount off of newegg because it was refurbished.
 
thanks for replying ya'll ... i will be getting another 3870 as soon as the prices drop and they are in stock again :D
 
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