Overclock.net › Forums › Industry News › Hardware News › [insidehw] ATI 48xx Architecture
New Posts  All Forums:Forum Nav:

[insidehw] ATI 48xx Architecture

post #1 of 3
Thread Starter 
Quote:
At the end of June, in Spain, we were introduced to a new series of 48xx graphics cards from ATI. We saw then only RV770PRO (4850) but at this moment 4870 (RV770XT) is also available. Even though our sources from AMD didn’t unveil why 4870 wasn’t shown on launching, we assume that some problems with quantities of available GDDR5 memory occurred. Considering that 4850 uses GDDR3 memory, it is no surprise that many retailers had them on stock. ATI 4870 will be sold, in beginning, exclusively with GDDR5 memory (this is the first graphics card that uses this memory) but AMD leaves a possibility that some innovative partner might launch later version that uses GDDR3 memory.


This shouldn’t be a problem because both cards use identical 256-bit Ring Bus for communication with memory and support GDDR3 and GDDR5 memory. This doesn’t imply appearance of 4850 with GDDR5 memory because it can compete with its stronger brother by price and certainly with performances. Beside difference in video memory that was used, cards differ also in GPU clocks, 625MHz for 4850 and 750MHz for 4870. Even we didn’t see 4870, on the end of the presentation ATI showed a very short “live†demo of Crysis and it looked phenomenal. Crysis worked very fast even in high resolution. Representatives from ATI confirmed that card that runs this demo is based on R700 architecture. Our assumption is that we, actually, saw some early engineer specimen in action, because the case was locked and undercovered and there was no chance to see inside. R700 should be found on the market under name of 4870 X2 just because it uses two 4870 GPUs. This card is still wrapped in secrecy and we didn’t come to any reliable information according its architecture. There’s only left to wait launch of this beast (based on multiGPU solutions) in August. This multiGPU vision is future stated by Matt Skynner, vice president of marketing, Graphics Products Group, AMD. Philosophy announced with launch of Spider platform on which you can improve performances simply by adding graphics cards, now gets elaboration: same way of thinking is now applied on graphics cards, using multiGPU configurations. When you have smaller GPUs with efficient consumption and excellent performances, further increases of graphics card performances is accomplished only by adding new GPUs, and not by new versions of faster, heavier and bigger consumption GPUs.

High performances were necessary to break “Sensory Barrier†– to present gamers with such a level of details never seen so far, only in movies. Don’t get us misunderstood, one 4850 still isn’t strong enough for something like that, but certain number of them can do the job and show something similar to impressive demo that was shown to us. In demo, our old acquaintance Ruby plays with battle robot and all that in very real street surroundings with lots of parked cars and tones of “sugar sweetsâ€.

“We’ll conquer nVIDIA in every segment and in every price range!†shouted Zwika from the stage. According to specifications of presented cards from 48xx series, something like that can easily happen. 38xx series GPU had 320 unified shader units and new generation has 800 unified shader units. “Much more than nVIDIA†says Zwika “which made its top processor in 65nm technology while RV770 GPUs are made in second generation 55nm technologyâ€. ATI can pull out from 2 to 2.5 times more processors from wafer of the same diameter, reducing waste rate and manufacturing costs per unit. For ATI this is already second generation of cards with DirectX 10.1 support that brings so many improvements regarding DirectX 10. These improvements can go up to 25%. That will become very important this autumn when new games series that will support simultaneously DirectX 10 and 10.1 come out. And for finals Zwika announced price tags: 199$ for 4850 and 299$ for 4870. nVIDIA’s answer on thrown down gauntlet came while this text was written. Price for 9800GTX was 300$ (a pipe dream for all buyers of 8800GT model) and now its price tag is 199$. Will this answer be enough to disturb ATI’s raise on market? We shall see… But one thing is for certain these are situations that end users can only benefit from. It’s even possible that these price reductions can turn out to be short-lived until 9800GTX cards vanish from stocks and make place for ace in a sleeve – 9800GTX+ made in 55nm technology. Leaving the stage, Zwika declared his certainty that nVIDIA GTX2xx series is last of monolithic cards kind and in next iteration they will also decide for multiGPU approach.

After Zwika, microphone goes to Eric Demers’ hands. Mr. Demers has a very interesting position – AMD Fellow. Demers drops information one after another, answering on unspoken questions of present journalists. The goal of 48xx series is to provide twice faster performances while using AA (Anti Aliasing, softening sharp edges) regarding to 38xx generation (AA is weak spot for 38xx). If we can judge by presented slides and our tests, they really managed to achieve this. Finally there is no big performances drop when you turn off AA, even more, with new generation difference in performances with turned on 8xAA or 4xAA is very small. If we compare it with card that was presented in Tunis last year, more exactly 13 months ago, it is obvious difference in performances with AA algorithm turned on (4 times more).
We remind you that comparison is made with 2900XT card, ATI’s plume from last year. In relation to previous generation, improvements are made to Clock Gating – base of Dynamic Power Management, technology in charge of ratio performance per watt. In case of smaller load of GPUs it turns off certain parts of chip additionally reducing consumption. The improvement was necessary considering the fact that every turning on/off of parts was lasting too long and as result you could see shuttering effect in Crysis and animation wasn’t so smooth anymore.

From bunch of slides that were moving like on conveyor belt, two sticks out. These two were predicted 4850 as competitor to 8800GT/8800GTS cards and 4870 as competitor to 9800GTX. Even if we did like this prophetic approach – at that point 9800GTX was 400$ and 4850 299$ - we didn’t like values for graphs of compared performances that were starting from 0.8 and not from 0.0 and visually already existing big difference in 48xx advance does look much bigger than it actually is.

If we take a look back on Blu Ray as de facto HD video standard in 2008, David Nalasco, ATI Technology Marketing Manager said that only in May this year Blu ray disks were sold more than during whole 2007. For ATI that means that time for implementation of second version Universal Video Decoder –UVD2 has come. That will bring for generation 48xx several novelties like for example Display Port, support for 7.1 Surround Sound and most interesting PictureInPicture possibility for HD Video reproduction. In spite of increasing number of sold BR disks, regular DVD is still far best seller video media. Because of increasing average screen resolution, ATI improved stretching picture techniques and now regular DVD movie can be stretched up to 1920x1200 resolution without increase in CPU usage and with much better visual display then you can achieve through software e.g. PowerDVD program. The army of HD camcorder owners also increases and they will benefit a lot from huge acceleration in 1080p video processing: compression of 60minutes of such video material takes around 10 hours on computer with average CPU and software processing or 32 minutes with AVT (Accelerated Video Transcoding) on 48xx series. Last year hardware acceleration was possible only in Adobe Premiere and now this possibility exists also for users of Cyberlink Power Director which costs much less.

It was very hard for us to describe every detail and impression from Malaga. We also didn’t mention before that this new chip has 956 millions of transistors or why are so great expectations for GDDR5 memory. We even didn’t dip into CrossFireX support that should be better than ever. You can read more about this subject in our review of Sapphire 4850/4850CF. GDDR5 memory chip speed will be at 1.8GHz x2 (3.6GHz) enabling this card beastly bandwidth to memory buffer. There is also new and improved Tesselation unit. Visually and maybe mainly the best part was demonstration of new RTS game from Electronic Arts, Battle Forge. Also we were shown technological demo in which GPU was used for searching the best path for units instead of former “CPU pathfindingâ€. Also ATI mentioned contract signed with Havoc that relates to hardware acceleration of certain physical model inside GPU. I think you can catch the point. Simply, there were so much newer, better, faster things that it was hard not to participate in complete euphoria. nVIDIA’s reaction with lower prices just suggest us that ATI hit the target. What’s left to us is to wait and see where will all this take us? For now nVIDIA 280GTX stays king of performances but ATI is the one that brought to gamers awesome gaming experience for price range around 150€.
Source
Edited by linskingdom - 7/4/08 at 5:52am
post #2 of 3
Quote:
Don’t get us misunderstood, one 4850 still isn’t strong enough for something like that, but certain number of them can do the job and show something similar to impressive demo that was shown to us. In demo, our old acquaintance Ruby plays with battle robot and all that in very real street surroundings with lots of parked cars and tones of “sugar sweetsâ€.
That demo was running on a 790FX/Phenom platform with a single 4870. If it was running on a cluster of GPUs it would hardly be impressive or relevant for the consumer.

Quote:
This shouldn’t be a problem because both cards use identical 256-bit Ring Bus for communication with memory and support GDDR3 and GDDR5 memory.
The RV770 doesn't use a ring bus any more.. They have a 'hub' for communications now.
Small box
(13 items)
 
  
CPUMotherboardGraphicsRAM
Intel 7700K ASUS Z270F Strix ASUS 1080 Ti FE Corsair Vengeance 16 GB 3200 MHz 
Hard DriveCoolingOSMonitor
Samsung 960 Evo Corsair H115i Windows 10 ASUS PG279Q 
KeyboardPowerCaseMouse
Unicomp Corsair CX850 Fractal Design Define C Logitech G PRO 
Mouse Pad
Steelseries QCK XXL 
  hide details  
Reply
Small box
(13 items)
 
  
CPUMotherboardGraphicsRAM
Intel 7700K ASUS Z270F Strix ASUS 1080 Ti FE Corsair Vengeance 16 GB 3200 MHz 
Hard DriveCoolingOSMonitor
Samsung 960 Evo Corsair H115i Windows 10 ASUS PG279Q 
KeyboardPowerCaseMouse
Unicomp Corsair CX850 Fractal Design Define C Logitech G PRO 
Mouse Pad
Steelseries QCK XXL 
  hide details  
Reply
post #3 of 3
Yeah, I thought the HD4k series moved away from the Ringbus technology, and back to a fast-switching hub?
The Replacement
(16 items)
 
  
CPUMotherboardGraphicsRAM
Core I5 6600K Gigabyte GA-Z170X-UD3 Ultra  EVGA GTX 750 Ti Crucial Ballistix Sport 2x16GB DDR4 2400 
Hard DriveOptical DriveCoolingOS
Mushkin Reactor 1TB LG Blu-Ray Burner Cryorig H7 Window 10 
MonitorKeyboardPowerCase
BenQ XL2420T Code 87 Clears Rosewill Photon 650 Fractal Design Core 3500W 
MouseMouse PadAudioAudio
CM Storm Xornet II Steelseries QCK+ Creative Sound Blaster Zx Sennheiser PC-360 
  hide details  
Reply
The Replacement
(16 items)
 
  
CPUMotherboardGraphicsRAM
Core I5 6600K Gigabyte GA-Z170X-UD3 Ultra  EVGA GTX 750 Ti Crucial Ballistix Sport 2x16GB DDR4 2400 
Hard DriveOptical DriveCoolingOS
Mushkin Reactor 1TB LG Blu-Ray Burner Cryorig H7 Window 10 
MonitorKeyboardPowerCase
BenQ XL2420T Code 87 Clears Rosewill Photon 650 Fractal Design Core 3500W 
MouseMouse PadAudioAudio
CM Storm Xornet II Steelseries QCK+ Creative Sound Blaster Zx Sennheiser PC-360 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Hardware News
Overclock.net › Forums › Industry News › Hardware News › [insidehw] ATI 48xx Architecture