What happens when you take a Radeon HD 3870 graphics card and slap a gigabyte of memory on it? That is the question of the hour, since our subject is Diamond's new card with just such a configuration. The Radeon HD 3870 has established itself as a pretty decent option among mid-range graphics cards, although it's squeezed by formidable competition from NVIDIA. Could doubling up on video memory allow the Radeon HD 3870 to distinguish itself from the likes of the GeForce 9600 GT and GeForce 8800 GT cards? Diamond's new take on the Radeon HD 3870 doesn't depart too radically from the established formula. The card comes with a default GPU clock of 830MHz. - TechReport

Diamond Radeon HD 3870 1GB Graphics Card Review

So well above the 775MHz baseline created by AMD but not quite as high as some of the cards which ranged as high as 850MHz. Similarly, the card's 1GB of GDDR3 memory comes clocked at 1740MHz, on a full 256-bit memory interface bus. The 512MB versions of the Radeon HD 3870 generally come with GDDR4 memory and consequently feature clocks as high as 2.4GHz. Diamond's ace is its larger memory size, coupled with the fact that GDDR3 memory tends to have lower latencies and thus perform better than GDDR4, clock for clock. On the flip side, GDDR4 memory chips tends to consume less power.

Diamond has outfitted this puppy with a little bit larger cooler than the norm. The oversized blower causes its enclosure to protrude slightly above the top of the card itself, much like a GeForce 8800 Ultra. The cooler doesn't look to be tall enough to create any sort of clearance problems in your average PC case, but those with small form factor systems may want to proceed with caution. The bigger question may be, how does having 1GB of memory onboard help matters? If you've been around the block a time or two like me, you'll probably know that video memory size can be a funny thing, though can lead to a minor increase.

Raising the Radeon HD 3870's memory size from 512MB to 1GB doesn't seem to improve performance measurably in any of the games we tested, even at a monster high definition resolution. As a result, the Radeon HD 3870 1GB delivers 3D gaming performance that's usually lower than the GeForce 9600 GT's. This outcome isn't really surprising to us. The Radeon HD 3870 cards seem to get along fine with 512MB of memory, even in extreme circumstances. We saw strong performance scaling from the CrossFireX multi-GPU scheme, which imposes some memory overhead, in Crysis with three and four RV670 GPU's.

And in the same situation, multiple G92 GPU's with 512MB memory ran into an obvious performance wall, while their 768MB cousins did not. AMD clearly has its GPU memory management mojo working better than NVIDIA's, so going beyond 512MB isn't yet necessary. This reality shouldn't be any sort of great calamity for Diamond's 1GB wonder. After all, video card makers slap outsized memory amounts on their products all of the time. Memory is cheap, and it does add a bit of future proofing. But this is the part where you can cue the scary music. Diamond is selling its Radeon HD 3870 1GB for $300 at multiple vendors.

Any way you slice it, though, that's expensive on par with the GeForce 9800 GTX, a product that vastly outperforms the Radeon HD 3870. So $300 will also buy you a pair of GeForce 9600 GT cards, one would be faster than the Radeon HD 3870, and two would roughly double its performance in many cases. All of which adds up to one inescapable conclusion, Diamond's Radeon HD 3870 1GB is a singularly poor value. We're all for pushing the boundaries with new memory sizes when the time comes, but nothing we've seen from this product justifies its price and that is what it is all about.