Radeon X1000 series

X1300 with GPU RV515 (heat sink removed)

This series is the budget solution of the X1000 series and is based on the RV515 core. The chips have 4 texture units, 4 ROPs, 4 pixel shaders, and 2 vertex shaders, similar to the older X300 – X600 cards. These chips basically use 1 "quad" (referring to 4 pipelines) of a R520, 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 research and development time and money. Because of its smaller design, these cards also offer lower power demands (30 watts), so they run cooler and can be used in smaller cases.[3] Eventually, ATI created the X1550, little more than an X1300 in disguise, and discontinued the X1300. The X1050 was based on the R300 core and was sold as an ultra-low-budget part.

Early Mobility Radeon X1300 to X1450 are based around the RV515 core as well.[6][7][8][9]

Beginning in 2006, Radeon X1300 and X1550 products were shifted to the RV505 core, which had similar capabilities and features as the previous RV515 core, but was manufactured by TSMC using an 80 nm process (reduced from the 90 nm process of the RV515).[10]

X1600 uses the M56 core which is based on RV530 core, a core similar but distinct from RV515.

The RV530 has a 3:1 ratio of pixel shaders to texture units. It possesses 12 pixel shaders while retaining RV515's 4 texture units and 4 ROPs. It also gains three extra vertex shaders, bringing the total to 5 units. The chip's single "quad" has 3 pixel shader processors per pipeline, similar to the design of R580's 4 quads. This means that RV530 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. Unfortunately, due to the programming content of available games, the X1600 is greatly hampered by lack of texturing power.[3]

The X1600 was positioned to replace Radeon X600 and Radeon X700 as ATI's mid-range GPU. The Mobility Radeon X1600 and X1700 are also based on RV530.[11][12]

ATI Radeon X1650 Pro

The X1650 series has two parts, which are quite different with regards to performance. The X1650 Pro uses the RV535 core (which is a RV530 core manufactured on the newer 80 nm process). Its advantage over X1600 is both lower power consumption and heat output.[13]

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 equipped RV570 core powers the X1950Pro, a high-performance card) to match its main competitor, NVIDIA's 7600GT.[14]

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 7 Series. When the X1800 hit the market in late 2005, it was the first high-end video card with a 90 nm GPU. ATI opted to fit the cards with either 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.[3]

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 R520 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.[3]

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.

The Xbox 360 uses a custom graphics processing unit called Xenos, which is similar to the X1800 XT.

Sapphire Radeon X1950 Pro

The X1900 and X1950 series fixes several flaws in the X1800 design and adds a significant pixel shading performance boost. The R580 core is pin compatible with the R520 PCBs meaning that a redesign of the X1800 PCB was not needed. The boards carry either 256 MiB or 512 MiB of onboard GDDR3 memory depending on the variant. The primary change between R580 and R520 is that ATI changed the pixel shader processor to texture processor ratio. The X1900 cards have 3 pixel shaders on each pipeline instead of 1, giving a total of 48 pixel shader units. ATI has taken this step with the expectation that future 3D software will be more pixel shader intensive.[15]

In the latter half of 2006, ATI introduced the Radeon X1950 XTX. This is a graphics board using a revised R580 GPU called R580+. R580+ is the same as R580 except for support of GDDR4 memory, a new graphics DRAM 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.[16]

The X1950 Pro was released on October 17, 2006 and was intended to replace the X1900GT in the competitive sub-$200 market segment. The X1950 Pro GPU is built from the ground up on the 80 nm RV570 core with only 12 texture units and 36 pixel shaders. 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.[17]