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AMD's Radeon HD 4830 graphics processor


The 4850's tough little brother picks a fight with a GeForce
— 11:01 PM on October 22, 2008

Ok, folks, this is gonna be a quick one. AMD has a brand-new Radeon to unveil today, and it's certainly worthy of our attention. However, Damage Labs is humming away with the sound of a great many things being tested right about now, so our time to devote to this new graphics card is limited. We'll be in and out of our look at the Radeon HD 4830 in no time, faster and cleaner than a celebrity marriage.


Little bro steps out
Yep, this new card is indeed called the Radeon HD 4830. The name tells you almost everything you need to know about this product, which would appear to be the last piece of AMD's 4000-series Radeon lineup to fall into place. Those of you who read our recent review of affordable graphics cards may recall that AMD didn't have much to offer between the (sensational for its price) Radeon HD 4670 at 80 bucks and the all-world Radeon HD 4850 at about $180. Well, that's where the 4830 comes in.

This new model is, like the 4850 and 4870, based on RV770 silicon, but in its tamest form yet. Yes, folks, the great product segmentation game continues with yet another chip having perfectly good—or possibly totally flawed—bits and pieces deactivated to maintain a neat separation between models. On the 4830, two of the RV770's 10 SIMD units have been disabled, reducing shader power (and likely performance) somewhat. Since those SIMD units are tied to texture management units, the GPU's TMU count has dropped proportionately. The end result: the Radeon HD 4830 has a total of 128 shader execution units—or 640 stream processors, in AMD parlance—and can filter up to 32 textures per clock.

That's it for the neutering, though. The 4830 keeps all four of the RV770's render back-ends and associated memory controllers intact, leaving it with an aggregate 256-bit memory interface. The card's GPU core runs at 575MHz, and it comes with 512MB of GDDR3 memory clocked at 900MHz (or 1800MT/s, for those of you keeping score at home.)

All of those numbers, acronyms, and GPU gobbledygook should add up to a pretty competitive product at its price. But, to give your brain a rest, here's a nice picture.


Ahhh...

Our sample card, which came from AMD, is based on the same basic board design as the Radeon HD 4850. The two are practically visually indistinguishable, right down to the single-slot cooler. However, AMD says board vendors will likely ship Radeon HD 4830 cards that use custom board designs and custom coolers, some of which will likely be of the dual-slot variety.

Somewhat unexpectedly, the 4830 also shares the 4850's board power rating of 110W, even with its lower clock speeds and shader-ectomy. Why? AMD says it's because 4830 cards may include chips that didn't quite pass muster for use in the Radeon HD 4850 or 4870. Those GPUs may need a little extra juice (that is, voltage) in order to do their thing. However, as you'll see, at least our copy of the 4830 didn't draw nearly as much power as our 4850.

The final bit of information you need to know about the 4830 before we move on to our performance testing? Pricing, of course. AMD's suggested "e-tail" price is $129, smack-dab in the middle of the hole in the Radeon HD 4000 lineup. That puts the 4830 almost directly opposite the GeForce 9800 GT, and AMD identifies that card as the 4830's most direct competitor.

Such things are never entirely straightforward, though, these days. Nvidia points not to the regular ol' 9800 GT but the higher-clocked variants like this MSI card for $119.99 at Newegg as the 4830's truest competition. The MSI's core clock runs at 680MHz, well above the 9800 GT's 600MHz baseline speed. Right now, that card packs a $20 rebate, as well, potentially improving its value proposition, if you're willing to risk seeing your 20 bucks ground up in the teeth of a bureaucracy designed to minimize redemption rates because you didn't write neatly enough on the little form.

Ah, I love rebates.

AMD can play this game, too, of course. Right here, you'll find a 4830 card from Sapphire for $129.99 with a $10 mail-in rebate attached. So, at the time of publication, the 4830's net price is a little higher than a hot-clocked 9800 GT, but that could change overnight. Prices could drop or rise, and rebates could expand or evaporate. Radeon board makers could intro 4830 variants with higher clock speeds, as well, or a killer new S3 Graphics product could turn the market on its ear. So who knows? Let's just look at how the Radeon HD 4830 performs, and I'll leave the fine-tuned deal-mongering to you.

Before we go on, though, I should mention up front that the GeForce 9800 GT card we've tested in the following pages is not a higher-clocked card. Instead, it's a Palit card with a bone-stock clock speed and 1GB of memory. That extra memory isn't likely to do much of anything for the 9800 GT at the resolutions we've tested, but higher clock speeds surely would—something to keep in mind.