Preview: Radeon HD 5830 (page 1: Introduction)

After pushing back the release date on several occasions, AMD finally decided to announce the Radeon HD 5830, based on the cut down Cypress GPU. Here are our first observations on the new DirectX 11 Radeon, that will, in principle, be available shortly.

Cut down Cypress

Generally after several months of GPU production, there’s an accumulation of pieces that didn't pass the validation process. Among these, some GPUs are partially functional and can be reused as cut down versions in a new product. A bit of time is needed before fixing the spec of such a derivative card as there are generally all sorts of faults in the reject pile: GPUs limited in terms of clocks, GPUs with SIMDs (processing + texturing) that don’t work, GPUs with non-functioning ROPs, GPUs on which only some units have clock problems etc. These all need to be sorted and a common spec needs to be found for a maximum number of these parts to allow the sale of a consistently defined product.

From its first appearance Cypress was rolled out in a slightly cut down version, the Radeon HD 5850 on which 2 SIMDs out of 20 were disabled and the clocks reduced. AMD goes even further with the Radeon HD 5830, with 6 SIMDs disabled as well as half the ROPs. It does however have a higher clock than the Radeon HD 5850. Astonishingly and in contrast to what usually happens, on the HD 5830 the disactivation of ROPs is not accompanied by a reduction in the size of the memory bus, which is still 256-bit – as we say, this is unusual and we’ll come back to it.

For this new card, AMD has decided to leave the design entirely in the hands of its partners who’ll be marketing their cards shortly. To allow us to evaluate performance however, AMD supplied us with an in-house Radeon HD 5830 but based on the stock design for the Radeon HD 5870. Most manufacturers seem to have opted for the same approach or for a similar custom design, making it a fairly big card:

The Sapphire Radeon HD 5830.

The only exception seems to be XFX, whose Radeon HD 5830 seems very short. It did however remind us of the Radeon HD 5750 512 MB from the same manufacturer that we have in our lab at the moment. After checking quickly, we can say it’s exactly the same card, sticker excepted. There’s no need to tell you that it’s impossible to put a Cypress GPU with its 256-bit memory bus and higher energy consumption on this PCB. In other words it’s a fake used to illustrate a product that apparently isn’t yet ready and as a result we don’t know what the final product will look like and if it will really be based on a shorter PCB.

The Radeon HD 5750 on the left and the XFX Radeon HD 5830 on the right.