Retesting the Radeon HD 4830: Too Few SIMDs Enabled

UPDATE: As certain as it seemed AMD was that no 560 SP 4830 boards had made it into the retail channel, it appears that they were, in fact, wrong. Fewer than 400 HIS Radeon HD 4830 boards made it into the channel. Here is the statement we recieved from AMD's Jay Marsden today:

AMD has identified that, in addition to reference samples of the ATI Radeon™ HD 4830 boards sent to media with a pre-production BIOS potentially impacting the card’s performance, a very limited number of ATI Radeon™ HD 4830 boards were released to market with the same pre-production BIOS. This is in no way hardware related, and an updated BIOS fully resolves the performance limitation.

Through consultations with AMD board partners, it has been determined with a high degree of certainty that fewer than 400 ATI Radeon™ HD 4830 boards from one AMD board partner, HIS, have reached the market with the pre-production BIOS incorrectly provided by AMD. As only a small number of HIS-branded ATI Radeon™ HD 4830 cards are impacted, we ask any customers that purchased an HIS-branded ATI Radeon™ HD 4830 to test the board using the GPU-Z utility (available at http://www.techpowerup.com/gpuz). If the GPU-Z utility reports fewer than 640 shaders, please visit the HIS website for information on how to update the card BIOS via a downloadable install utility.

We had thought that retail parts would be fused to a certain number of active SIMDs to avoid soft mods and that review samples were probably based on test/engineering hardware AMD was using when developing the final specs for the Radeon HD 4830. It seems that theory is out the window, but we will continue to provide updates as we learn more.

Thursday, AMD launched their newest RV7xx variant completing their line up in time for the holiday season. As is usual with a new graphics card launch, we published a review. The hardware looked good and offers gamers that really want to play games with good quality but don't need high resolution performance a solid money saving option.

But a number of curious things happened throughout the course of the day yesterday. We first noticed an interesting article from the makers of GPU-z. Techpowerup.com posted a story on the fact that their reference sample from AMD only enabled 560 SPs rather than the full 640 we were all promised.

We were certainly intrigued by this, so we picked up the updated GPU-z and it told us we also only had 560 SPs. Now, this isn't a common occurrence at all, and multiple other issues could have been at work. We wanted to hold off on commenting until we could learn what was really goning on and bring you the whole story. It took us a while to sort everything out, and with this issue out there it's understandable why AMD needed some time to track down the causes and potential effects of this problem.

All the details we have point to the missing SP problem being limited to review samples only. AMD's partners should not have this issue pop up in the wild. This is good news for consumers, and good news for AMD as well. We saw that the 4830 wasn't a bad part, but because our tests were run with 87.5% of the full compliment of SIMDs our numbers don't reflect the full performance potential the hardware has.

AMD got us an updated BIOS for the card and we have new numbers showing the performance improvement. We have updated our tests from the other day to better reflect the relative performance end users can expect.

It is also worth noting that AMD has supplied all their partners with an updated BIOS as well to cover the just-in-case scenario. They believe they know why this happened and so believe that there is no cause for concern over retail parts exhibiting this problem. But giving their partners a new BIOS is a good idea anyway as it covers all the bases.