Multi-GPU Scaling: Two 3850s = One 8800 GTX?

AMD only sent us a pair of Radeon HD 3850s for this review (believe it or not, we had to beg to get a single 3870), so our only CrossFire numbers come from this setup. That being said, the performance is quite respectable:

Believe it or not, but a pair of these $179 Radeon HD 3850s actually gives you the same performance as a single GeForce 8800 GTX.

 Multi-GPU Scaling (2560 x 1600) Radeon HD 3850 CF GeForce 8800 GT SLI
Oblivion 1.7x 1.87x
Unreal Tournament 3 1.48x 1.66x

 

Scaling looks pretty good from the Radeon HD 3850, however it's still not as good as what NVIDIA is able to achieve with the 8800 GT. NVIDIA consistently achieves about 11% better scaling from one to two GPUs than AMD.

The other problem with CrossFire is that it simply doesn't always work, so a pair of 3850s is not necessarily a better option than a single 8800 GT or GTX. Case in point would be the two other games that we wanted to include here: Quake Wars and Call of Duty 4, both gave us lower frame rates with CF enabled than without. AMD's release notes for the Radeon HD 3800 drivers informs us that some applications may show a performance decrease with CF enabled, so we're not too surprised.

While it'd be nice to be able to purchase two cheap cards and get better performance than the best out there, there are simply too many caveats to really embrace the idea.

Out with the Old, in with the Mid-Range Power Consumption
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  • ViRGE - Thursday, November 15, 2007 - link

    Testing
  • dustinfrazier - Thursday, November 15, 2007 - link

    Going on a year for Nvidia dominance and boy does it feel good. I bought my 8800gtx pair the first day they were available last year and never expected them to dominate this long. God I can't wait to see what comes out next for the enthusiasts. It get the feeling it is gonna rock! I really wanna see what both companies have up their sleeves as I am ready to retire my 8800s.

    I understand that these latest cards are great for the finances and good energy savers, but what does it matter if they already have a hard time keeping up with current next gen games at reasonable frame rates, 1920x1200 and above? What good does saving money do if all the games you purchase in 08 end up as nothing but a slide show? I guess I just want AMD to release a card that doesn't act like playing Crysis is equivalent to solving the meaning of life. Get on with it. The enthusiasts are ready to buy!
  • abhaxus - Thursday, November 15, 2007 - link

    err, tried to do a hardocp logo and it hid everything in the previous post.
    text is:

    I've read that... but then I've also read on AT and that with current bios releases the asus boards are fine to around 360-400 FSB. I haven't O/C'ed an intel chip since the Celeron 300A so I am pulling my hair out trying to decide if it's worth it to plan for going SLI or just get a P35 board and stay with a single card.

    sorry to go so OT. the article was very good in typical anand style.
  • JonathanYoung - Thursday, November 15, 2007 - link

    Just browsing through the article and this graphic caught my eye:

    Monitors command buffer to *ASSES* level of GPU utilization

    Not sure if this is an AMD or AT graphic, but you guys might want to correct it!
  • Anand Lal Shimpi - Thursday, November 15, 2007 - link

    That'd be an AMD graphic, if I had an editable source I'd correct it, but all I've got is the PDF :)

    Take care,
    Anand
  • imaheadcase - Thursday, November 15, 2007 - link

    I have heard quite a few people dislike those line graphs you use, the eyes just don't register lines well vs bars (one reason why long lines are not put in center of roads and they use bars to make the line) Why not stick to bar graphs like you do in the power consumption page?

    The eyes like things to conform to a shape, or should I say the brain. :) Quick glance at a bar graph is easier for the brain to compute than following lines.
  • strikeback03 - Thursday, November 15, 2007 - link

    Regarding lines on road, this is somewhere on US83 between La Pryor and Leakey in southern Texas.

    http://img.photobucket.com/albums/v315/strikeback0...">http://img.photobucket.com/albums/v315/strikeback0...

    I have no idea what that road marking means.

    As for the line charts, I like them better than a multiple bar chart would to display all the same info on a single chart.
  • Anand Lal Shimpi - Thursday, November 15, 2007 - link

    It's always tough finding a good balance, since I can cram so much more information into a line graph than a bar graph. I've just been toying with these things for the 8800 GT and this review, I'll see if I can come up with something better for the next round :)

    Take care,
    Anand
  • feraltoad - Thursday, November 15, 2007 - link

    Can't please everyone I guess. I really like the line graphs. I think it is much easier to compare cards scaling across resolutions and gives a better overview of performance in relation to one another.

    You could use hand puppets and then everyone would be happy. I know I would :)
  • JNo - Thursday, November 15, 2007 - link

    I second that - lines ftw

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