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HD 7850 Crossfire

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April 17, 2012 7:39:29 PM

Well, I finally got my HD 7850 today, I went with MSI Twin Frozr III.

Before my new rig, I used a PC from circa 2003 so it's not surprising that I'm at loss of words.

So far I tried games like Penumbra, Amnesia, Batman, Team Fortress 2 and Left 4 Dead 2 and results are excellent.

I'm considering upgrading to Crossfire in about a year, when the price drops and when drivers mature a bit.

I can't find any HD 7850 CF reviews yet, probably because the card is still new.

Is there anyone out there with HD 7850 CF experience who could tell me more about it?

Things that concern me are micro stuttering and driver support, which AMD is not very famous for.

Thanks for input. :) 

More about : 7850 crossfire

April 17, 2012 7:48:08 PM

crossfire when you plan to use eyefinity no need to Xfire with just a single monitor.
April 17, 2012 9:06:47 PM

And what about future proofing? I'm sure single HD 7850 won't last me for 2-3 years if I want to play on highest details.
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April 17, 2012 10:09:26 PM

If you're playing those game you don't need more than a 6850 lol. Try Crysis and Metro 2033 and The Witcher 2 - put that card through it's paces!

Anyway I doubt there's need to worry about CF right now. That card will play just fine for a long time. If you want max settings in all games at 1080p or higher you'll need to go CF... Anyway 7850s should easily be available at retail for 2 years and longer if you don't mind buying used. I don't see any need to rush out and spend cash unless you feel the need for more performance.
April 17, 2012 11:02:53 PM

I'm not rushing, I won't buy a new one in at least a year. :) 

Those are not the only games I play, just some that I tried so far.

I just tried BF3 on ultra settings, 2x MSAA and 8x AF at 1680x1050 and it's going very very smoothly. I didn't measure FPS yet, but I plan to. However, it doesn't lag or twitch even the slightest.

Highest recorded temperature is 59 °C which pleases me. :)  Also, you can't hear it over the sound of my case fan (Scythe Slip Stream 1900 RPM - that thing is like a turbine, both airflow and sound).
April 18, 2012 5:30:11 AM

BF3 frame rate was mostly around 55-60 FPS, occasionally dipping to high 40s and jumping to mid 70s. I'm pretty happy. :) 
April 25, 2012 8:24:36 PM

what power supply are you using and how many watts would you need for a 7850 crossfire?
April 25, 2012 8:27:05 PM

I'm using XFX XXX Edition 650W which has 52A on 12V rail.

Not sure if it's enough, but some people seem to think it is.

I'd feel safer with 750W so I'll wait for more reviews and user experience considering HD 7850 is still fairly young GPU.
April 25, 2012 8:35:50 PM

Using this calculator for PSU wattage I managed to get this:

478W needed for 2x HD 7850 @ 100% load
708W needed for 2x GTX 570 @ 100% load

That is for overclocked 2500K, 1 HDD, 3 regular fans, 3 LED fans, 2 DDR3 sticks and 1 USB device.

Is the difference really that big? And I find it hard to believe that 500W PSU would suffice for HD 7850 CF. :/ 
April 25, 2012 9:42:15 PM



So, yes, 570s are a lot more consuming. 202W for a pair of 7850s, plus another 100W for a CPU. HDD, DVD, lights, etc, are all fairly low consumption, like maybe 10-15W.

This doesn't mean anything when you overclock, though. Especially if you add voltage. Power consumption can go way up, 100W+ on a single component.
April 25, 2012 9:47:11 PM

That's really helpful. :) 

I overclocked my CPU, but nothing extreme, 4.0 GHz now. I probably won't go over 1.35V Vcore, ever. That shouldn't add more than 20-30W on top of standard 95W TDP, right?

I don't plan to overclock GPU as it's already factory overclocked. I suppose factory OC is nothing extreme either.
April 25, 2012 9:57:27 PM

Wow, that's bad. Is that IB only or same applies to SB?

My stock Vcore is 1.18V - 1.19V and I increased it to 1.28V.
April 25, 2012 10:30:22 PM

Well the theory applies to all CPUs and GPUs, but as for how much it increases I don't really know. I'm sure other overclocking reviews of other CPUs test the power usage, but this is just one I saw recently.
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