Radeon X1000 series

Radeon R520 (Radeon X1K Series)

File:R520.jpg
Release date	2005-2006
Codename	Fudo
Cards
Entry-level	Radeon X1300, X1350
Mid-range	Radeon X1600, X1650
High-end	Radeon X1800, Radeon X1900, Radeon X1950
API support

ATI's "R520" core (codenamed Fudo) is the foundation for a line of DirectX 9c 3D accelerator x1000 video cards. It is ATI's first major architectural overhaul since the "R300" core and is highly optimized for Shader Model 3. The Radeon X1000 series using the core was introduced on October 5 2005

Features

X1800 chip

X1800 chip

The R520 core architecture is referred to by ATI as an "Ultra Threaded Dispatch Processor". This refers to ATI's plan to boost the efficiency of their core, instead of going with a brute force increase in the number of processing units. A central pixel shader "dispatch unit" breaks shaders down into threads (batches) of 16 pixels (4x4) and can track and distribute up to 128 threads per pixel "quad" (4 pipelines each). When one of the shader quads becomes idle, due to a completion of a task or waiting for other data, the dispatch engine will assign the quad with another task to do in the meantime, with the overall result being a greater utilization of the shader units, theoretically. With such a large number of threads per "quad", ATI created a very large general purpose register array that is capable of multiple concurrent reads and writes and has a high-bandwidth connection to each shader array. This provides temporary storage necessary to keep the pipelines fed by having work available as much as possible. With chips such as RV530 and R580, where the number of shader units per pipeline triples, the efficiency of pixel shading drops off slightly because these shaders still have the same level of threading resources as the less endowed RV515 and R520.

The next major change to the core is with its memory bus. R420 and R300 had nearly identical memory controller designs, with the former being a bug fixed release designed for higher clock speeds. R520, however, differs with its central controller (arbiter) that connects to the "memory clients". Around the chip there are two 256-bit ring buses running at the same speed as the DRAM chips, but in opposite directions to reduce latency. Along these ring buses are 4 "stop" points where data exits the ring and going into or out of the memory chips. There is actually a fifth stop, one that is significantly less complex, designed for the PCI Express interface and video input. This design allows memory accesses to be far quicker though lower latency by virtue of the smaller distance the signals need to move through the GPU, and by increasing the number of banks per DRAM. Basically the chip can spread out memory requests faster and more directly to the RAM chips. ATI claims a 40% improvement in efficiency over older designs. Again, the smaller cores such as RV515 and RV530 receive cutbacks due to their smaller, less costly designs. RV530, for example, has two internal 128-bit buses instead. This generation has support for all recent memory types, including GDDR4. In addition to ring bus, each memory channel now has the granularity of 32-bits, which improves memory efficiency when performing small memory requests.

File:Ruby's Revenge 1024.jpg

Ruby returns in The Assassin

The vertex shader engines were already of the required FP32 precision in ATI's older products. Changes necessary for SM3.0 included longer instruction lengths, dynamic flow control instructions, with branches, loops and subroutines and a larger temporary register space. The pixel shader engines are actually quite similar in computational layout to their R420 counterparts, although they were heavily optimized and tweaked to reach high clock speeds on the 90 nm process. ATI has been working for years on a high-performance shader compiler in their driver for their older hardware, so staying with a similar basic design that is compatible offered obvious cost and time savings.

At the end of the pipeline, the texture addressing processors are now uncoupled from pixel shader, so any unused texturing units can be dynamically allocated to pixels that need more texture layers. Other improvements include 4096x4096 texture support and ATI's 3Dc normal map compression sees an improvement in compression ratio for more specific situations.

Raster OP engines are also uncoupled from rendering pipeline similar to GeForce 6 series.

As is typical for an ATI video card release, a selection of real-time 3D demonstration programs were released at launch. ATI's development of their "digital superstar", Ruby, continued with a new demo named The Assassin. The demo showcased a highly-complex environment, with high dynamic range lighting (HDR) and dynamic soft shadows. Ruby's latest nemesis, Cyn, was composed of 120,000 polygons. [1]

Unlike its Xenos sibling in Xbox 360, the R520 is a more traditional non-unified shader design, in that it has functional units designed only for their specific task (vertex shaders and pixel shaders).

Display output units also support dual-link DVI output, and HDCP. However, using HDCP requires external ROM to be installed, which were not available for early models of the video cards. RV515, RV530, RV535 cores include 1 single and 1 double DVI link; R520, RV560, RV570, R580, R580+ cores include 2 double DVI links.

Variants

X1300 series

The X1300 series is the budget card of the X1000 series. It replaces the X300/X600/X550 series from the previous generation, and shares similar capabilities. The chip carries a 4 pipeline design, similar to those older cards. However, it has all the same capabilities of the higher end boards. In fact, it is said that the chip uses 1 "quad" (4 pipelines per quad), whereas the faster boards use just more of these "quads". For example, the X1800 uses 4 "quads". This modular design allows ATI to build a "top to bottom" line-up using identical technology, saving time and money. Also, the X1300 has more modest power-draw requirements (30 watts), so it runs cooler and fits in smaller cases.

The X1300 series used the RV515 core. There are 3 main variations of the X1300. The HyperMemory variant is quite different from the regular X1300. The local memory is clocked at 400 MHz, higher than the standard X1300, but its bus width is very limited at 32-bit, meaning it has far less available local memory bandwidth. This lowers the cost of the board (to ATI) significantly by reducing board complexity and using fewer and cheaper RAM chips. The onboard memory plays the role of a sort of cache, while most memory operations are performed on system RAM instead. The X1300 Pro gets faster memory, using DDR2 memory as compared to the DDR memory of the normal X1300.

Quite recently, VisionTek, a partner of ATI, ported the Radeon X1300 to the PCI bus.[2] This is ATI's very first DirectX 9 chip available on PCI; until now NVIDIA has had this niche all to itself, except for the now-discontinued XGI Technology Volari V3XT. DirectX 9 on PCI is a rather small niche for now, but with Windows Vista demanding DirectX 9 for its signature Windows Aero interface, it is likely to grow dramatically as those who bought integrated-graphics systems without AGP or PCIe slots in the last few years prepare to upgrade to Vista. The X1300 is also currently the only widely available PCI-Express x1 video card, manufactured by HIS.

In September 2006, the X1300XT was released, which is a X1600Pro with lower clock settings. Some manufacturers have decided to implement GDDR3 memory instead of the regular DDR2 memory, and overclock the RV530 GPU to match the X1600XT/X1650PRO clocks. A X1300XT with such memory and clocks is a X1600XT/X1650Pro in disguise.

X1400 series

A slightly faster Mobility Radeon X1300. Uses the same GPU core as X1300, but with a higher clock speed. Performance comparisons put it well behind X1600 but ahead of X600. [3]

X1550 series

Renamed X1300 series after AMD acquisition of ATi. The Radeon X1550 Pro is now available in standard PCI [4]

X1600 series

X1600 uses the RV530 core, a core that is quite a bit different from the RV515 of X1300 and the R520 of X1800. The X1600 is positioned to replace Radeon X600 and Radeon X700 as ATI's mid-range GPU.

It shares design philosophy with the X1900, in that it has a far different ratio of pixel shader processors. ATI has stated that the X1600 is designed with a far greater shader computational load, a prediction of future game workloads. Whereas the X1300 and X1800 have an equal pixel shader to texturing unit ratio, which targets a more equal workload of shaders and texturing in games, the RV530 of X1600 alters this to 12 pixel shaders and 4 texturing units. The chip's single "quad" has 3 pixel shader processors per pipeline. This means the chip has the same texturing ability as the X1300 at the same clock speed, but with its 12 pixel shaders it encroaches on X1800's territory in shader computational performance. While the performance is no where near that of an x1800 it still manages to lead the x1300 by a decent margin across the board. The X1600 also receives a boost in the vertex shader department, with the addition of 3 more units (total of 5) over the X1300. Its architecture is reflected in its performance; although the X1600 XT is slower than the nVidia 6600GT in older games, it outperforms it in newer games that utilize more intense shader effects.

The X1600's core clock speeds are similar to X1300's while the memory attached is usually clocked higher. However, benchmarks show that the X1600 is a decent step up from the x1300. The reasons for this is that the X1600 while having some of the same limitations has much greater ability to process complex shaders having triple the number of pipelines. Unfortunately for ATI, benchmarks also show that the X1600's intended competitor, the nVidia 7600GT, is a much faster card despite being comparably priced.

X1650 series

The X1650 series has 2 parts, which are quite different performance wise. The X1650Pro uses the RV535 core (which is a RV530 core manufactured with the newer 80nm process). Its clock speeds are almost the same compared to the X1600XT; so the only advantage of the X1650Pro is both lower power comsumption and heat output, which translate into higher overclocking headroom. The other part, the X1650XT uses the newer RV570 core (also known as the RV560) although cut down in processing power (note that the fully fledged RV570 core powers the X1950Pro, a high performance card) to match its main competitor, nVidia's 7600GT. The X1650XT has a disadvantage, though: it consumes a little more power, and feeds from the PSU. The 7600GT outputs less heat when in full load, and doesn't need external power.

X1700 series

The X1700 series is mainly based around the mobility strain used in Notebooks. It represents a small step up from the X1600 series, and retains dedicated video memory.

X1800 series

ATI X1800 logo

ATI X1800 logo

Originally the flagship of the X1000 series, the X1800 series was released with little fanfare due to the rolling release and the gain by its competitor at that time, NVIDIA’s GeForce 7800 series. The reason for the delayed release was that ATI engineers had found a bug within the core caused by a faulty 3rd party 90 nm chip design library which greatly hampered clock speed ramping, and so they had to "respin" it for another revision. The problem had been almost random in how it affected the prototype chips, making it quite difficult to finally identify. When the R520 hit the market in late 2005, the X1800 was the first high-end 90 nm GPU. ATI opted to fit the cards with either with 256 MiB or 512 MiB on-board memory (foreseeing a future of ever growing demands on local memory size). The X1800XT PE was exclusively on 512 MiB on-board memory. The X1800 replaced the R480-based Radeon X850 as ATI's premier performance GPU.

With R520's delayed release, its competition was far more impressive than it would have been if the chip had made its originally scheduled Spring/Summer '05 release. Like its predecessor X850, the R420 chip carries 4 "quads" (4 pipelines each), which means it has similar texturing capability if at the same clock speed as its ancestor, and the NVIDIA 6800 series. Contrasting the X850 however, R520's shader units are vastly improved. Not only are they fully Shader Model 3 capable, but ATI introduced some innovative advancements in shader threading that can greatly improve the efficiency of the shader units. Unlike the X1900, the X1800 has 16 pixel shader processors as well, and equal ratio of texturing to pixel shading capability. The chip also ups the vertex shader number from 6 on X800 to 8. And, with the use of the 90 nm Low-K fabrication process, these high-transistor chips could still be clocked at very high frequencies. This is what gives the X1800 series the ability to be competitive with GPUs with more pipelines but lower clock speeds, such as the NVIDIA 7800 and 7900 series that use 24 pipelines.

X1800 was quickly replaced by X1900 because of its delayed release. X1900 was not behind schedule, and was always planned as the "spring refresh" chip. However, due to the large quantity of unused X1800 chips, ATI decided to kill 1 quad of pixel pipelines and sell them off as the X1800GTO.

X1900 series

File:Wp-RX1900-001-1024X768b.jpg

ATI Radeon X1900 advertisement, using the R580 core

The X1900 series fixes several flaws in the X1800 design and adds a pixel shading performance boost. Interestingly, the R580 core is pin compatible with the R520 PCBs meaning that a redesign of the X1800 PCB was not needed. X1900 boards carry either 256 MiB or 512 MiB onboard GDDR3 memory depending on the variant. The primary change between R580 and R520 is that ATI changed the pixel shader processor per pipeline ratio. The X1900 cards have 3 pixel shaders on each pipeline, giving a total of 48 pixel shader units. ATI has taken this step with the expectation that future videogames will be more pixel shader intensive than previous ones.

The Radeon X1900GT, simply an X1900XT that has been clocked lower and 4 pixel processors disabled, supports Crossfire without a master card. It was created to compete with the 7900GT, though it trailed in performance, it was also generally cheaper. A shortage of R580 cores that can clock to 575MHz resulted in the creation of a Revision 2 X1900GT running at 512MHz, however with a higher memory clock (1320MHz). They are most easily recognizable by the new reference heatsink, the same used on the X1950Pro.

X1950 series

The X1950 XTX is a graphics board using the R580+ GPU. It is unclear what has been changed in this new revision as it is clocked at the same speed as the R580 aboard X1900 XTX and manufactured on the same 90 nm silicon process. For a performance gain, the new X1950 XTX uses GDDR4 memory, a new RAM technology that offers lower power consumption per clock and offers a significantly higher clock rate ceiling. X1950 XTX clocks its RAM at 1 GHz (2 GHz DDR), providing 64.0 GB/s of memory bandwidth, a 29% advantage over the X1900 XTX. The card was launched on August 23, 2006.

The X1950 Pro is released on 17 October 2006 with a MSRP of $200 and intended to replace the X1900GT in the competitive <=$200 market segment. The X1950 Pro GPU is built from the ground up with only 12 texture units and 36 pixel shaders. It is based on the 80nm RV570 core, allowing to draw and dissipate less power than the 90nm R580-based cards.

The X1950 Pro is the first ATI card that supports native Crossfire implementation by a pair of internal Crossfire connectors, which eliminates the need for the unwieldy external dongle found in older Crossfire systems. Performance-wise, the X1950 Pro trails slightly behind a X1900XT 256 MiB, due to a deficit of 4 texture units and 12 pixel shaders, as well as lesser GPU and memory clocks. This card is available for AGP.

PowerColor, an ATi partner, was one of the first to announce an AGP X1950Pro, this card is also shown to come pre-installed with an Accelero X2 cooler. Other ATI partners such as Visiontek, GeCube and Sapphire have also started to ship AGP X1950Pro cards in both 256 and 512 MiB versions, and all these are now available online and in some retail stores. The X1950GT was released in Janurary and is basically an underclocked X1950 PRO, however remains unsupported (as mentioned in catalyst release notes) in Vista with the latest catalyst drivers (ver 7.2).

On October 20, there was a quiet launch of the X1950XT, though none were actually on stock at retailers. The X1950XT features the same board, cooler, and GDDR3 memory as the X1900XT ,however, using the R580+ core with higher clock speeds.

Chipset table

Desktop Graphics Boards
Board Name	Core Type	Die Process	Clocks (MHz) Core/RAM	Core Config1	MTex/s2	MTri/s3	Memory Interface	Memory Bandwidth	Notes
X1300 HM	RV515	90 nm	400/400	4:4:4:2	1600	200	64-bit	6.4 GB/s	32-128 MiB local RAM.
X1300	RV515	90 nm	450/250	4:4:4:2	1800	225	128-bit	8.0 GB/s	Can be 64 or 128-bit bus
X1300 Pro	RV515	90 nm	600/400	4:4:4:2	2400	300	128-bit	12.8 GB/s
X1300 XT	RV530	90 nm	500/340	4:12:4:5	2000	625	128-bit	10.9 GB/s	renamed Radeon X1600 PRO
X1600 Pro	RV530	90 nm	500/390	4:12:4:5	2000	625	128-bit	12.5 GB/s	128/256/512 MiB
X1600 XT	RV530	90 nm	590/690	4:12:4:5	2360	738	128-bit	22.1 GB/s	128/256 MiB
X1650 Pro	RV530 / RV535	90 / 80 nm	600/700	4:12:4:5	2400	750	128-bit	22.4 GB/s	renamed Radeon X1600 XT
X1650 XT	RV560	80 nm	575/690	8:24:8:8	4600	1150	128-bit	22.1 GB/s	256 MiB, "native" CrossFire
X1800 GTO	R520	90 nm	500/500	12:12:12:8	6000	1000	256-bit	32.0 GB/s
X1800 GTO²	R520	90 nm	500/500	16:16:16:8	8000	1000	256-bit	32.0 GB/s
X1800 XL	R520	90 nm	500/500	16:16:16:8	8000	1000	256-bit	32.0 GB/s
X1800 XT	R520	90 nm	625/750	16:16:16:8	10000	1250	256-bit	48.0 GB/s	256/512 MiB
X1800 XT-PE	R520	90 nm	700/800	16:16:16:8	11200	1400	256-bit	51.2 GB/s	512 MiB
X1900 GT	R580	90 nm	575/600	12:36:12:8	6900	1150	256-bit	38.4 GB/s
X1900 GT rev.2	R580	90 nm	512/660	12:36:12:8	6140	1024	256-bit	42.2 GB/s	new PCB, cooler and HDCP support
X1900 XT	R580	90 nm	625/725	16:48:16:8	10000	1250	256-bit	46.4 GB/s	256/512 MiB; similar ratio of units as RV530
X1900 XTX	R580	90 nm	650/775	16:48:16:8	10400	1300	256-bit	49.6 GB/s
X1950 GT	RV570	80 nm	500/600	12:36:12:8	6000	1000	256-bit	38.4 GB/s	"native" CrossFire (internal bridge), HDCP (1/07), No Vista support (Cat 7.2)
X1950 PRO	RV570	80 nm	575/690	12:36:12:8	6900	1150	256-bit	44.2 GB/s	"native" CrossFire (internal bridge), HDCP
X1950 XT	R580+	90 nm	625/900	16:48:16:8	10000	1250	256-bit	57.6 GB/s	Uses GDDR3 (256 MiB) and A31 chip rev.
X1950 XTX	R580+	90 nm	650/1000	16:48:16:8	10400	1300	256-bit	64.0 GB/s	Uses GDDR4 and A31 chip rev.
X1950 XTX UE	R580+	90 nm	670/1050	16:48:16:8	10720	1340	256-bit	67.2 GB/s	"Uber Edition", signed by Dave Orton
Mobility Radeons and Integrated Graphics Processors
Board Name	Core Type	Die Process	Clocks (MHz) Core/RAM	Core Config1	MTex/s2	MTri/s3	Memory Interface	Memory Bandwidth	Notes
note: clock speeds can vary between notebooks.
MR X1300 HM	M52 / RV515	90 nm	400/325	4:4:4:2	1600	200	64-bit	5.2 GB/s	32-128 MiB local RAM.
MR X1300	M52 / RV515	90 nm	400/325	4:4:4:2	1600	200	128-bit	10.4 GB/s
MR X1350	M62 / RV515	90 nm	?/?	4:4:4:2	?	?	128-bit	? GB/s
MR X1400 HM	RV515	90 nm	432/345	4:4:4:2	1728	216	64-bit	5.5 GB/s	32-128 MiB local RAM.
MR X1400	RV515	90 nm	432/345	4:4:4:2	1728	216	128-bit	11.0 GB/s
MR X1450	M64 / RV515	90 nm	?/?	4:4:4:2	?	?	128-bit	? GB/s
MR X1600 HM	M56 / RV530	90 nm	445/350	4:12:4:5	1780	556	64-bit	7.52 GB/s	128-256 MiB local RAM.
MR X1600	M56 / RV530	90 nm	470/470	4:12:4:5	1780	556	128-bit	11.2 GB/s	Back Bias process technology
MR X1700	M66 / RV530	90 nm	?/?	4:12:4:5	?	?	128-bit	? GB/s	Back Bias + Strained Silicon
MR X1800	R520	90 nm	450/500	12:12:12:8	5400	900	256-bit	32.0 GB/s
MR X1800 XT	R520	90 nm	550/650	16:16:16:8	8800	1100	256-bit	41.6 GB/s
MR X2300	M64 / RV515	90 nm	?/?	?	?	?	?-bit	? GB/s	Renamed from X1000 series to X2000 series for low-end notebooks

• Bold rows indicate major core types.
• ¹ (Texture Units:Pixel Shaders:ROPs:Vertex Shaders). All chips of this generation have 1 texture mapping unit (TMU) per pixel pipeline, but the operation of TMU is not tied to any particular pixel pipe.
• ² MTex/s = Million Texels per second, a measure of texturing fillrate. All chips of this generation have equal texture and pixel fillrates because of having only a single TMU per pipeline.
• ³ MTri/s = Million triangles per second, a measure of the core's geometric calculation capabilities. Related to core speed and the number of vertex shaders.

See also

• List of computer games that require Pixel Shaders
• Comparison of ATI Graphics Processing Units
• ATI Rage
• NVIDIA
• XGI
• S3 Graphics

References

• Beyond3D R520 Preview
• Beyond3D RV5xx Preview
• Beyond3D R580 Preview
• Beyond3D 3D Chip Tables
• Tech Powerup 3D Chip Table
• Adrian's Rojak Pot Chip Table
• Tech Powerup Powercolor X1300 HyperMemory 2 Review
• Bjorn3D R580 preview
• DinoxPC.com Radeon X1600Pro Crossfire
• ATI official Website
• Faster, Quieter, Lower: Power Consumption and Noise Level of Contemporary Graphics Cards (7/2006)