ATI’s Radeon X1950 XTX

by John Reynolds

Introduction

The Radeon X1950 XTX is something of a milestone, the last DirectX9 graphics board from the company, ATI, that ushered in DX9 GPUs with the release of the Radeon 9700 Pro over four years ago. With the upcoming release of Windows Vista and its inclusion of DirectX10, the market is duly expecting entirely new architectural designs from the graphics IHVs built for the Shader Model 4.0 specifications found in the forthcoming update to Microsoft’s API. Yet as for now, both ATI and NVIDIA are keeping their DX10 GPU details somewhat under wraps, and, in the case of the former company, using refresh parts like the Radeon X1950 XTX to satisfy market needs until Vista’s arrival. Refresh products rarely introduce new technology, serving instead to generally increase performance of an existing architecture or design, and the X1950 is no exception to this rule. Let’s take a quick look at what changes this new offering brings to ATI’s Radeon 1000 series before diving into test beds and benchmarks.

What’s New? Faster Memory, Slower Fan

The Radeon X1950 XTX is the first consumer graphics board to hit the market using GDDR4 memory. Moreover, the memory modules are clocked at an amazing 1GHz (2GHz effective), giving the X1950 a significant memory bandwidth increase over its predecessor, the Radeon X1900 XTX. We’re talking 64GB per second of memory bandwidth compared to the 49.6GB of the X1900, which works out to be a roughly 30% increase. An improved cooling solution designed for the 1950 helps make this high memory clock rate possible, and support for the memory type itself is due to a somewhat new GPU, the R580+. For all intents and purposes, the R580+ is identical to the Radeon X1900’s R580 except that GDDR4 support was added to the memory controller. GDDR4 as a memory type or standard isn’t significantly different from previous types, it simply runs faster, so supporting the new memory didn’t require a major overhaul of the graphics chip.

The X1950 XTX, like the X1900 XTX, has a core clock speed of 650MHz, giving the new part theoretical fill rates identical to that of the older graphics board. Where the X1950 should shine is in gaming situations where the frame rate is predominantly limited by the graphics board’s memory bandwidth. Shader-limited operations, however, should see virtually identical performance numbers between the two parts. The benchmark testing conducted for this article, therefore, attempted to focus on this by using more demanding settings (detailed below).

As mentioned above, beyond higher memory bandwidth the X1950 also offers hardware enthusiasts an improved cooling solution. The cooler shared by both the X1800 and X1900 didn’t exactly garner ATI a lot of accolades among the aurally sensitive, and the company has attempted to address this criticism with the X1950’s cooling assembly. The new design sports a larger copper heatsink, and, like its predecessor, requires two slots, but the primary improvement is in the size and position of the fan. ATI moved the new fan to the rear of the graphics board, which still allows air to be pulled across the length of the heatsink, and the fan itself is larger and therefore has a slower spin. According to ATI, this results in reduced noise levels compared to the the previous cooler while still effectively cooling the 1GHz GDDR4. The test system’s noise levels were measured using a digital sound meter to put these claims to the test, as discussed below in the environmental characteristics section of this article.

The Radeon X1950 XTX had a MSRP of $450 at launch several months ago, $200 less than the MSRP of the X1900 XTX earlier this year. The latter can now be found online at the mid-$300 price range, so let’s see if the X1950 justifies its higher price from a performance perspective.

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