ATI Radeon HD 4850 Preview: AMD Delivers Performance for the Masses
by Anand Lal Shimpi & Derek Wilson on June 19, 2008 5:00 PM EST- Posted in
- GPUs
Assassin's Creed
Two GeForce 8800 GTs in SLI outperform a single GeForce GTX 280, and two Radeon HD 4850s in CrossFire outperform the 8800 GT SLI, so AMD manages to outperform NVIDIA's brand new GT200 with a pair of cheaper, slower cards. The two actually end up performing like a GeForce 9800 GX2 here as well.
It's not so much that the Radeon HD 4850 is ultra competitive, but rather that the GTX 280 isn't terribly competitive with NVIDIA's own $400-$500 multi-GPU solutions.
Assassin's Creed has a ~60 fps frame rate cap, so the flat performance of the 4850 in CrossFire simply indicates that it kept bumping off of the frame rate limiter resulting in static performance throughout all three resolutions.
Oblivion
While CrossFire tends to not scale as consistently as SLI, when it does, it scales very well. The performance of two 4850s is nearly double that of a single card and it puts AMD at the absolute top of the performance charts here.
The Witcher
The Witcher is a good example of an area where CrossFire fails to scale - despite the Radeon HD 3870 X2 scaling, we could not get the 4850 to show any performance benefit with two GPUs. It could be an issue with the 4850 drivers or a special trait of the 3870's driver, at this point it's tough to tell.
Bioshock
While we see scaling at 1920 x 1200, at 2560 x 1600 there's no benefit to two 4850s over one. We could be bumping into a memory bandwidth limitation or some continued strangeness in AMD's CrossFire drivers.
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docmilo - Thursday, June 19, 2008 - link
I browsed on over to the Egg and did a search on 4850. A whole bunch of cards popped up at $199.99 and one even has a rebate! I wonder how long until it stops saying "Buy Now" and goes to "Autonotify".chizow - Thursday, June 19, 2008 - link
You guys did a nice job of covering both the pros and cons of the 4850 and CF, showing some of the pitfalls of relying on multi-GPU solutions for performance. You also made mention that similar performance gains were seen long ago with the 8800GT.That said the 4850 is certainly a good part from AMD and there's definitely some very interesting things they've done with this card. You hinted at a lot of them with the architectural changes but there's a few other sites that hinted at some of the changes. Its clear ATI has drastically improved their memory controllers and cache design along with their render back ends for AA performance.
I think the real thing to keep an eye on though is how AMD managed to get near 100% scaling with CF. Extremetech hinted at improved memory controllers and a gpu communications "Hub" here http://www.extremetech.com/article2/0,2845,2320865...">http://www.extremetech.com/article2/0,2845,2320865... for improved performance between GPUs. I'm sure you guys will cover these improvements in detail in your complete review, but it looks like that hyper transport mechanism you alluded to.
MadBoris - Thursday, June 19, 2008 - link
Nice to see AMD staying competitive, plus keeping prices down.I think the days of me spending $400+ on a video card are behind me, atleast for the foreseeable future. You have to provide alot more than 10% performance increases for an extra $250 NVIDIA.
I'm rather surprised NVIDIA has not really capitalized on taking a huge performance lead and crown with all the AMD post merger dust settling.
I'm pleasantly surprised that AMD is continuing to excel with HW. If only they would bring back an AIW card, I'd buy one, but my current 8800GTS is not so outmatched that it is worth upgrading to anything this generation.
Good article Anand.
fungmak - Thursday, June 19, 2008 - link
Looking at the CF perfomance of other sites who used cat 8.6, IIRC were a lot better than the current AT results.Just wondering if there is an intention to update using cat 8.6?
derek85 - Friday, June 20, 2008 - link
I second this, I'm sure 8.6 came with some nice optimizations on 770s.DerekWilson - Friday, June 20, 2008 - link
we did not use catalyst 8.5 drivers.we used the very latest beta drivers ATI could get us.
Wirmish - Friday, June 20, 2008 - link
And did you use the Radeon HD 4800 Series Hotfix (6/20/2008) ?http://support.ati.com/ics/support/default.asp?dep...">http://support.ati.com/ics/support/default.asp?dep...
;)
Nighteye2 - Thursday, June 19, 2008 - link
The big question for the comparison between this card in CF and the GT200 will not be the classic framerates here - but the performance of games that use the GPU for part of the physics processing. The GT200 has lots of compute power to spare for physics, can 2 4850's in CF match that?FITCamaro - Friday, June 20, 2008 - link
With 800 shaders it wouldn't surprise me.Wirmish - Friday, June 20, 2008 - link
He talk about CF...So it's 1600 shaders !