The Radeon 5550 is a strange beast, quietly released by AMD a couple of months ago with very little in the way of fanfare. It may only be separated by the well-established 5450 by a single digit, but under the hood this card is very different. Whereas the 5450 is part of the entry level ‘Cedar’ family of cards, the 5550 is actually the lowest rung of the ‘Redwood’ series, also encompassing the well-established Radeon 5670.
AMD has disabled a fifth of the shader processors available on the GPU, meaning the 5550 has 320 active rather than the 400 of the 5670. The number of texture units takes a similar cull from 20 down to 16, though the Raster Operator count remains at 20. In terms of clock speed the 5550 is shipped with a GPU clock of 550MHz and a memory clock of just 800MHz for its 1GB of DDR2. Despite a 128-bit interface this diminutive speed means the 5550 is extremely bandwidth starved, delivering just 1/5th of the throughput of the GDDR5-equipped 5670.
Despite a marked reduction in specification this Sapphire Radeon 5550 is offered at a price almost identical to the manufacturer’s own 5670. This is because the Ultimate Edition features a 100 percent passive cooler, pitching it squarely at the HTPC crowd. In this capacity the card is well specified. It has enough shader grunt to allow both AVIVO and Vector Adaptive Deinterlacing features to be enabled at the same time (something the 5450 is not able to deliver at Full-HD) as well as the nirvana of Blu-ray audio standards; bitstreamed Dolby TrueHD and DTS-HD Master Audio. This is delivered seamlessly via the HDMI 1.3a port which had no issues handshaking with our Denon receiver. All of these features are of course also available from the faster 5670, although that card has a fan; albeit a quiet one.
In order to test performance we tasked the 5550 with the most demanding PC game we know of; Crysis Warhead. As it’s not a flagship class card we restricted ourselves to a resolution of 1280 x 1024. Nevertheless at gamer settings the 5550 could only manage a paltry 13fps on our Core i7-equipped test rig. By contrast the 5670 managed a playable 31fps while the 5450 was closer than we expected at 8fps. Reducing the settings to “performance” yielded a smoother experience but those expecting graphics even close to the cinematic effects depicted on the box will be sorely disappointed.
Considering its lowly spec we were quite surprised by the amount of heat the 5550 gives off. On an open test bench the heat sink became too hot to touch comfortably, with the GPU itself peaking at over 80 degrees when running our benchmarks. Whilst this didn’t result in any visual artefacts, you’ll probably want a case fan in a slim-line HTPC box to keep the card happy, thereby removing any advantage it has by being passive in the first place.
As the lowest grade (and more importantly the only passively-cooled) card that can perform ATi’s full suite of video-enhancing technologies simultaneously, the 5550 finds itself in a niche position. If you must have these features and will not tolerate a fan-equipped cooler, it’s your only choice. Those willing to put up with a quiet fan will find themselves far better served by a 5670. It costs no more, runs far cooler and is in a totally different league when it comes to performance.
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