The ATI Radeon HD 4830 Stream Processor Mix-up

The Stream Processor Mix-up - 560 vs. 640 SPs

The Stream Processor Mix-up - 560 vs. 640 SPs

If our review of the new Radeon HD 4830 piqued your interest and you cared enough to do some research of your own, you'll probably be aware of the little identity crisis that plagues some of the HD 4830 cards. If not, let us tell you about it.

Briefly, what happened was that while updating GPU-Z to include support for the new HD 4830, the good people at techPowerUp! noticed that some of the cards they have in hand had 560 stream processors instead of the advertised 640. This is worrying as the HD 4830 is fundamentally a HD 4850 with 160 stream processors disabled and this is usually done by manipulating fuses inside the GPU or on the substrate, which is often an irreversible process. If the fault is indeed hardware-related, it could potentially lead to massive product recalls - costing ATI precious time and money.

Ensure that the number of stream processors aka. shaders is 640 and nothing else!

Fortunately, the problem has been made known and according to AMD (the parent company of ATI), the problem is entirely BIOS-related and can be rectified by a simple BIOS update. They also reiterated that this problem has absolutely nothing to do with the hardware. This is what AMD said:

"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 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."

Unfortunately, our HIS Radeon HD 4830 card happened to be one of the affected cards, which explained why it consistently performed below the other two HD 4830 cards we had. Happily, however, the problem was easily rectified by flashing the BIOS with an easy to use downloadable BIOS update utility. With the HIS Radeon HD 4830 sorted out, we proceeded to test it again, just to make sure all 640 stream processors are properly enabled. Here are the updated results.

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