February 25, 2010, AMD’s Graphics Product Group finished its transition from the Radeon HD 4000 to 5000 generation as the Radeon HD 5830 closed the last gap between the Radeon HD 5770 and Radeon HD 5830 and made the whole series of AMD’s DirectX 11 compatibles complete. A junior Radeon 5800 series model had indeed been lacking as there had been a large price gap between the earlier released Radeon HD 5770 (below $160) and Radeon HD 5850 ($399). It could be filled in by either a tuned-up version of Radeon HD 5770 or a cut-down variant of Radeon HD 5850. AMD chose the latter option and based its Radeon HD 5830 on the RV870 Cypress core, the same core as in the Radeon HD 5850 but with a cut-down configuration.
This is a wise solution considering that the Cypress itself is a highly complex chip incorporating over 2 billion transistors. Despite the polished-off tech process, there is going to be a large share of defective chips which, however, might work just fine if the defective subunits were turned off. This turning off of defective subunits helps the manufacturer put such chips to good and profitable use rather than scrap them altogether. That’s a standard practice among GPU makers. In fact, the Radeon HD 5850 itself has a small part of its shader and texture-mapping processors turned off. As for the Radeon HD 5830, there are 480 ALUs, 24 TMUs and 16 (out of 32) raster back-ends disabled in its RV870 processor.
This must have been intended as a means to maximize the amount of chips that could be used for the Radeon HD 5830. To make up for such a drastic loss in functional subunits and offer a product that wouldn’t be inferior to the Radeon HD 4890, the GPU clock rate was increased to 800 MHz. Formally, the Radeon HD 5830 was indeed as good as its predecessor in terms of rasterization subsystem and even better in terms of computing and texture-mapping resources. Its scene fill rate was lower due to the lower GPU frequency (800 against 850 MHz) but the new card’s texture sampling rate was much higher, at least theoretically. Considering its DirectX 11 and Shader Model 5.0 support, the Radeon HD 5830 looked a worthy replacement to the Radeon HD 4890.
Alas, the first round of tests published in our review Intermediate Link: First Look at ATI Radeon HD 5830 1024 MB brought rather disappointing results. The Radeon HD 5830 proved to be inferior to the previous-generation Radeon HD 4890 and GeForce GTX 275 in a number of tests while having a comparable price. That was not good news for the new card, but we did not have a “real” Radeon HD 5830 then and had to use a cut-down Radeon HD 5870 card.
AMD’s partners have offered their Radeon HD 5830 products since then and you can easily find one in shops. We’ve got one such card, produced by XFX, for our today’s tests. Let’s see if this Radeon HD 5830 is any better than the card we tested in our first report.