Radeon HD5830 details leak

Not as powerful as we hoped

DETAILS OF AMD’s soon to be launched ATI Radeon HD5830 have made their way onto the web via the Chinese website IT168.com. Parts of a PowerPoint presentation have turned up alongside several pictures of partner cards.

It seems like we were spot on with regards to the pricing, as the suggested retail price will be $250 or less, although AMD has placed the cards in the $200+ Enthusiast segment, so don’t expect them to be available for less than that for quite some time. This is still significantly cheaper than the Radeon HD5850, but there’s a good reason for this.

There’s no secret that the HD5830 was going to be a cut down HD5850, but it looks like AMD cut off a bit more than expected. The HD5830 only has 1120 stream processors, that’s 320 less than the HD5850 (which has 160 less than the HD5870). It also has a mere 56 texture units, down 16 from the HD5850 (which has only 8 less than the HD5870). It also only has half the ROPs compared to the HD5850. Despite a core clock speed of 800MHz (up 75MHz over the HD5850) all the cuts means that the HD5830 has lost a lot more performance than anticipated.

According to the product specifications the HD5830 will only manage 1.79 TFLOPs compared to 2.09 TFLOPS for the HD5850. It also has a lower texture fill rate at 44.8 GTexles/s compared to 52.2 GTexles/s for the HD5850. Although this isn’t nearly as bad as the pixel fill rate which is down to 12.8 GPixel/s which is less than the HD5770 which manages 13.6 GPixel/s. The Z/Stencil buffer is also slower than the HD5770 by some 3GSamples/s and this is almost half the performance of the HD5850.

AMD has kept the same memory clock and bandwidth as on the HD5850 for the HD5830, but this is a minor consolation considering the fairly heavy cuts on the GPU. Still, AMD wouldn’t want the HD5830 to be too close to the HD5850 in terms of performance, as then the sales of HD5850 cards would drop. We’re going to have to wait for some benchmarks to see how well this card performs compared to the HD5770 as well as Nvidia’s GTX260 which will be its closest rivals in terms of pricing.

The HD5830 also has a higher maximum board power of 175W which seems a little bit odd. The higher clock speed should account for an increase in power usage, but the fused off parts should in return have accounted for a reduction in power usage. The idle power is slightly less than that of the 5850 though.

It looks like AMD has allowed its partners to build their own cards based on the HD5830, although the first round of cards appears to be mostly based on the reference design. However, judging by the pictures on IT168, we’ll see a lot of custom coolers on these cards and Gigabyte even has one with a few heat pipes sticking out and dual fans.

We’re still a couple of days away from the actual launch, but the cat’s out of the bag. We’re a little bit disappointed with the specifications of the HD5830. We expected AMD to trim off 160 stream processor rather than 320. Having half the ROPs will also penalize the HD5830, although we’re not sure if AMD has enough granularity to offer a 24 ROP version of not. There’s always a cost versus performance issue, but we’re not going to write off the HD5830 until benchmark numbers are out.S|A

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