Introduction

Hot on the heels of the launch of the Radeon X1950 Pro two weeks ago, today ATI’s assault on the mainstream graphics market takes another bold step forward with the introduction of the Radeon X1650 XT.

Once again ATI’s enlisting the services of a new GPU, in this case, its name is RV560, and once again the new GPU is built on TSMC’s 80-nm manufacturing process and has ATI’s CrossFire dual-GPU technology built into the graphics core. This means that every Radeon X1650 XT graphics card supports CrossFire out-of-the-box. There’s no need for proprietary CrossFire master graphics cards, and the much maligned CrossFire dongle isn’t necessary either.

ATI Radeon X1650 XT card

The Radeon X1650 XT and X1950 Pro

GeForce 7600 GT and X1650 XT pictured together

The really sweet part about ATI’s Radeon X1650 XT though is its price. The card carries an MSRP of just $149. That puts it squarely in GeForce 7600 GT territory. Ever since it was first introduced in March, the GeForce 7600 GT has been an enormous hit for NVIDIA, and a thorn in the side of ATI. Its got 12 pixel shaders and 5 vertex shaders, and sports clock speeds similar to the Radeon X1600 XT, but our testing has shown that the GeForce 7600 GT delivers significantly more performance in today’s games.

Since the GeForce 7600 GT’s debut, ATI’s basically been forced to slash prices on their Radeon X1600 line. Originally the GPU was supposed to debut as high as $249, but those plans were quickly scuttled and the price was adjusted to $199. When the 7600 GT arrived the X1600 XT’s price was reduced to around $150, as the X1600 XT performed more similarly to NVIDIA’s 7600 GS than the 7600 GT.

Now ATI’s taking a real stab at dethroning the GeForce 7600 GT with their Radeon X1650 XT, and its RV560 GPU has all the right specs on paper to do just that.

X1650 XT (top) X1600 XT (bottom)

The X1650 XT sits between the GeForce 6600 GT and 7600 GT

Radeon X1650 XT CrossFire

RV560 is armed with 24 pixel shaders, and 8 vertex shading units. In comparison, this is twice the number of pixel shaders as the Radeon X1600’s RV530 GPU, which only contained 12 pixel shading units, and three additional vertex shaders than RV530. ATI also outfits RV560 with 8 texture address units and 8 render back-ends (ROPs), this is twice times the number of texture units and ROPs as the Radeon X1600, which was the achilles heel of that GPU, particularly with older titles that weren’t pixel shader heavy.

Like the Radeon X1600 XT, the Radeon X1650 XT’s RV560 GPU retains ATI’s ring-bus memory architecture. The GPU feature a 256-bit internal ring bus, with a 128-bit interface to the board’s memory.

In terms of clock speeds, the Radeon X1650 XT’s RV560 GPU runs at 574MHz, while the board’s memory runs at 675MHz (1350MHz effective). Both of these figures are a little slower than RV530, which ran at 590MHz core/690MHz memory.

GPU Comparison
Card	Core Clock Speed (MHz)	Pixel Shaders	Vertex Shaders	ROPs	Texel Fill-rate (Mtexels/sec)	Memory Speed (MHz)	Memory Bandwidth (GB/sec)
Radeon X1950 Pro	575	36	8	12	6900	1380	44.2
Radeon X1650 XT	575	24	8	8	4600	1350	21.6
Radeon X1800 GTO	500	12	8	12	6000	1000	32
Radeon X1600 XT	590	12	5	4	2360	1380	22.1
GeForce 7900 GS	450	20	7	16	9000	1320	42.2
GeForce 7600 GT	560	12	5	8	6720	1400	22.4