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AMD's Radeon HD 6450 graphics card


Please, sir, I want some more...
— 11:21 PM on April 6, 2011

We don't generally spend much time exploring the world of entry-level graphics processors. It's not for a lack of interest, but out of a sense of propriety. For as long as we can remember, that market has been populated by the lame bastard children of more glorious designs—blessed with right components to make a truly great GPU, yet cursed with an insufficient number of them and condemned to disappoint.

Thus entry-level GPUs hobbled about the world, taking shelter in bargain bins and luring penny pinchers with double-digit price tags. "Only $49.99," the sticker on the box might say. "$39.99 after a mail-in rebate!" Some even attempted deception, bulking up with cheap, slow RAM, so that at a glance, uneducated shoppers might mistake them for better products capable of using up a large frame buffer.

Unfortunate souls who took pity upon these misshapen atrocities—or were fooled by them—often realized all too late that, far from being upgrades, entry-level cards only perpetuated the mediocre performance to which they'd grown accustomed. Silicon might heat up, and tiny cooling fans might race noisily, but games that should have been beautiful were warped into unsightly slide shows, like faded Polaroids of what they'd have looked like... if only you'd sprung for a faster card.

Is the wind of change blowing at last? It would seem so, thanks in no small part to Intel's Sandy Bridge processors and their shockingly capable integrated graphics. With the performance floor set at a reasonable level for the first time in, well, forever, entry-level cards have a chance to shine. Or rather, they must, lest they be rendered irrelevant for good.

AMD's Radeon HD 6450 belongs to a new breed of entry-level graphics cards, which is designed not to offer the absolute bare minimum GPU makers can get away with, but to provide enough of a step up from Sandy Bridge's IGP to justify the asking price—in this case, $54.99. AMD's pitch is that the Radeon HD 6450 delivers not just superior performance, but also little perks like DirectX 11 capabilities, support for GPU compute applications, and the ability to drive three displays at once. Better game compatibility ought to be somewhere in there, too.

In short, while this card scrapes the bottom of the barrel, it doesn't seem like as much of an afterthought as its predecessors. Could it be that, in 2011, a graphics card priced at $55 finally delivers acceptable performance in current games? Surely luxuries like antialiasing and advanced shader effects must be off-limits, but could the Radeon HD 6450 set the bar for "good enough," provided you're more interested in having fun than soaking in eye candy? Considering the stagnating hardware requirements of games and the ever-increasing horsepower of graphics silicon, that doesn't sound like too outlandish a premise.

Anatomy of a $55 graphics card
The Radeon HD 6450 is based on Caicos, a lilliputian graphics processor with a die area my measurements peg at around 75 mm². (Compare that to the 255 mm² GPU of the recently released Radeon HD 6790.) Caicos keeps processing resources to a minimum, with only 160 shader ALUs, or stream processors, and the ability to filter eight textures and output four pixels per clock cycle. The path to memory is only 64 bits.

Caicos is wrapped in two different variants of the new Radeon: one with 1GB of DDR3 memory and another with 512MB of GDDR5, pictured below:

The GDDR5 variant is clocked slightly faster, with a 750MHz GPU and a memory speed of 800-900MHz. (Our model has 900MHz RAM, which translates into about 28.8 GB/s of peak memory bandwidth.) The slower, DDR3-based variant of the Radeon HD 6450 runs at 625MHz and clocks its memory at 533-800MHz. AMD says both versions cost the same, though.

As you might expect, these spartan computing resources mean equally stingy power utilization: only up to 27W for the GDDR5 card and 20W for its DDR3 sibling. Idle power is about 9W, less than one of those regular-sized swirly light bulbs. In other words, the Radeon HD 6450 might just be the sort of GPU you'd want to stick in a home-theater PC—or perhaps a small-form-factor desktop machine tuned for light gaming.