ATI Radeon HD 4850 and 4870: RV770 Has Arrived

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As we've already explained, the initial line-up of Radeon HD 4800 series cards will be comprised of the single-slot Radeon HD 4850 and dual-slot Radeon HD 4870.


   


AMD is touting the Radeon HD 4850 as the first single-GPU solution to offer 1TFLOPs of compute power, thanks to its 625MHz RV770 GPU.  The card features GDDR3 memory and has a max power of about 110W.  As you'd probably expect, the Radeon HD 4870 is markedly more powerful.  Although based on the same GPU, the 4870 is clocked higher at 750MHz, and thus offers 1.2TFLOPs of compute power. The Radeon HD 4870 also makes use of newer GDDR5 memory technology and has a higher max power of 160W.  More on the cards themselves a little later.

Low level specs aren't what make the Radeon HD 4800 series cards stand out; it's the RV770 GPU that's really interesting.  It turns out that AMD was able to crank the SP count up from 320 on the older RV670 to a beefy 800 on the RV700. AA and Z/Stencil performance are enhanced as well, and the number of texture units has been increased from 16 to 40.  What's somewhat surprising about all of these changes though, is that AMD was able to do it with "only" a 44% increase in transistors.


   


AMD was able to do this by redesigning virtually all of the functional blocks within the GPU.  The 800 stream processing units are grouped in a new SIMD core layout, and the texture units, ROPs, and cache have been restructured to minimize transistor count, while also increasing performance.  We should also point out that the ring-bus memory controller introduced with the X1K series has been replaced with a new memory controller that can make use of GDDR5 memory.


   


With the RV770, AMD claims that the SPs in the GPU offer 40% more performance per square millimeter, and that more aggressive clock gating offers improved performance per watt.  Likewise, the newly streamlined design of the RV770 texture units reportedly offer 70% more performance per square mm with double the texture cache bandwidth and large increases in 32- and 64-bit filter rates.

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 Hi All.  If you liked this article, please Digg it...

http://digg.com/hardware/ATI_Radeon_HD_4850_and_4870_RV770_is_Here_CrossFire_Tested

Thanks!

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Aside from the heat output this definately sounds like a better buy (the 4870) than does the GTX 280 -- after all, is it really worth 2x the cost [of the 4870] for a card that performs not-so substantially better? Yes the 280 will out perform it but who, I ask of you, would truely take advantage of this performance increase that would not be able to have an enjoyable experience with ATI's counterpart?

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I was looking forward of reading this review at HH :)

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great review, just wish overclocking was tested, since according to some reports after an after market cooler, you can get it to be around the gtx 280 level.

i think its clear that this gen, ati is king. sure nvidia has the better performance but for 2x as much id much rather crossfire the 4870

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This was definatly a good reveiw. Im impressed with both the ATI and the nvidia cards.The implementation of DDR5 is definatly a plus at the same time with me the price point to performance ratio is probably going to have a factor in my decision when I get in a financial situation to do so.It already has got me excited thinking about an aftermarket cooler just to see what kind of numbers I can acheive in lowering the temps and OCing options. When I get ready to pick up one of these Bad Boys they,ll be more updates to this reveiw by HH.Good read HH!

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What I thought was most significant is that two 4850's in Crossfire performs almost identically to a single GeForce GTX 280 in all tests, but the dual 4850 setup ends up being around $250 cheaper (2x$199 vs $649). That is a huge deal. Even considering potential Crossfire scaling issues with certain games, you're still clearly ahead with a $250 savings.

The best part is, since the 4850's are single-slot cards that use a single 6-pin power connector, dual 4850s technically have the same physical footprint as a single GeForce GTX 280. Granted, the Crossfire setup would produce more heat and consume more power than a single GTX 280, but the difference isn't huge. I don't even see the point on a single GTX 280 setup now.

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LovelyCrap:
What I thought was most significant is that two 4850's in Crossfire performs almost identically to a single GeForce GTX 280 in all tests, but the dual 4850 setup ends up being around $250 cheaper (2x$199 vs $649). That is a huge deal. Even considering potential Crossfire scaling issues with certain games, you're still clearly ahead with a $250 savings.

The best part is, since the 4850's are single-slot cards that use a single 6-pin power connector, dual 4850s technically have the same physical footprint as a single GeForce GTX 280. Granted, the Crossfire setup would produce more heat and consume more power than a single GTX 280, but the difference isn't huge. I don't even see the point on a single GTX 280 setup now.
 

 

Well thats my thinking on it even at a savings of $250 over the 280,s Certainly the option of ati,s single card slot would be in my price range and of course the pricing as it is I think will cause nvidia to be a little more competitive in its pricing!

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I too am very pleased by the results of this review, but where's my HD video IN? We still need cards that can take in an HD signal with a DVI or HDMI plug. Regardless, I'll probably be buying one of these before long.

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 well ya never know. nvidia may slash the prices on the gtx 280 now to stay in the game otherwise I don't see them selling.

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I doubt the 280 will be available for under 6 bills for at least a couple months and probably won't be under 5 till next year... just my oppinion.

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