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ATI Radeon HD 4850, Crossfire Compatibilty/Performance

Last response: in Graphics & Displays
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May 21, 2009 5:19:22 PM

I have a Sapphire ATI Radeon 4850 Video Card.
PCI Express 2.0
512MB
625MHZ (Core Clock)
993 MHz (Memory Clock)

My Asus P5Q Pro MB has (2) PCI Express 2.0 slots. I want to be prepared for upgrading in the future.

If I chose to add another Video Card that is exactly the same as my current, and then connect them with the CrissFire Bridge, would my new Video Card stats be...

1024MB
1250MHz (Core)
1986MHz (Memory)

I want to know how I would compare "CrossFiring" (2) lower end cards against a higher end card.

Also, I am guessing that I can "CrossFire" any of the Sapphire PCI Exp 2.0 cards regardless of the quality of the card, is that right?

I just want to know how to handle my upgrade.

What do I need to make sure matches up when soing a "CrossFire"? PCI Exp 2.0, Memory, Clock Speeds, etc...

How do I know what all my options are wihtout looking at things that are out of the question.

Finally, when "CrossFiring" would I be able to use a "Native HMDI Output" card to connect to me HD LCD via HDMI in place of the current DVI-->HDMI connector I am using on my existing card.

I don;t know enough about Video Cards to know if any of these are even valid questions.

Hopefully everything was clear for the most part.

Look forward to everyone's input.
May 21, 2009 9:48:24 PM

From what i know 2 x 4850s is slightly better than 1 4870 and is slightly worse than a 4870 x2.

Having two video cards in SLI/CF i believe up-scales the preformance but isnt a 100% increase in preformance. So having 2 4850s could Dramaticly increase your FPS in one game and not increase at all in another (it won't double your FPS). Results vary but you wont be getting 200% preformance from the two video cards, but more likley 150%. A second video card now or later on down the line is recommened by many people and by me.

You can crossfire any 4850 from any brand. However CFing a 4850 and 4870 isnt advised as the 4870 will only run as fast as the 4850 (basically having 2 4850s).

Jordan.

a b U Graphics card
May 21, 2009 9:53:40 PM

I run 2 Visiontek 4850's in a crossfire configuration (although crossfire is disabled the majority of the time so i can run 3 monitors). I'll try to cover all your questions.

1.) No adding the second card doesnt double the values of the card. Running two 512 meg cards in crossfire is still like having 512 megs of ram. Clock speeds arent increased but instead you have multiple GPU's (like the difference in a single core processor and dual core). The increase from running crossfire is nowhere near double. You are lucky to get a 50% gain at most and this is only if the particular game can utilize multiple GPU's, alot of games get no performance increase from crossfire.

2.) You can crossfire any of the saphire cards or even a different brand.

3.) Check ATI's site but you can crossfire alot of different cards but the performance gain is going to be limited by whichever card has the lowest memory / speed.

4.) Yes you can still use both outputs on the primary card when crossfiring. This means you can use the HDMI out and the DVI out.

If you havent bought your second 4850 yet you might want to consider a 4870 or even higher. I have seen the 4870's going for only slightly more then the 4850's after mail in rebate.
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