AMD: The Radeon HD 6790 can't be unlocked

By on April 8, 2011, 10:00 AM
Earlier this week AMD released the Radeon HD 6790. As previously reported, the card is based on a cut-down version of the "Barts" GPU first seen in the Radeon HD 6800 series, with 160 fewer Stream Processors than the HD 6850, 8 fewer Texture Units and half the ROPs. At the current price of $150 it's not really the best deal, but some hoped its hardware could be re-enabled via a BIOS flash to get a free speed boost. Unfortunately, that will not be the case.

The folks at X-bit labs confirmed this in talks with AMD's Evan Groenke, who said: "It is not something that should be possible on the 6790. Those SIMDs are fused off." So unlike early versions of the Radeon HD 6950, which could be turned into a 6970 with a simple tweak, it looks like the Radeon HD 6790's Barts GPU is locked at the hardware level.


At least the card is said to be a good overclocker, and with board partners implementing their own cooling solutions users should be able to squeeze some extra performance without much trouble. However, going for an Nvidia GeForce GTX 460 (768MB) at the same price or paying a just few extra bucks for the more powerful Radeon HD 6850 sounds like a better option. The cheapest 6850 costs $165 on Newegg and you can even get it for less after a mail-in rebate.



User Comments: 8

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fpsgamerJR62 said:

Bummer indeed, but not surprising considering AMD's approach to building mid-range cards. I wonder if AMD would ever build something like the 4770 again.

red1776 red1776, Omnipotent Ruler of the Universe, said:

fpsgamerJR62 said:

Bummer indeed, but not surprising considering AMD's approach to building mid-range cards. I wonder if AMD would ever build something like the 4770 again.

In what respect gamer?

If I remember correctly, the 4770 was a replacement when they ran short on 4830 silicone. They cut the bus from 256 to 128, but gave it GDDR5 in place of GDDR3. It was slightly faster at lower resolutions and the 4830 was a touch faster at higher resolutions.

dividebyzero dividebyzero, trainee n00b, said:

Bummer indeed, but not surprising considering AMD's approach to building mid-range cards. I wonder if AMD would ever build something like the 4770 again.

You might see a similar card eventuate in the HD7xxx series.

Remember that the HD 4770 was the first card produced that used TSMC's 40nm process. It, as a mainstream product, was deemed low risk and was effectively a trial horse for the new process shrink. In the end a good strategy by AMD since the HD 4770 GPU suffered from voltage leaking- something more noticeable when nvidia's Fermi arrived using the same process.

The 4770 was a proof of concept exercise first and foremost, and a retail product secondly- hence the fact that the 4770 never appeared as a volume part.

Common wisdom (nvidia apart) would seem to dictate that the first product out of a semiconductor foundry on a new process mode would be a smaller die where problems in the die's construction would cost less to rectify with subsequent steppings/revisions, and number of usuable chips per wafer are likely to be higher.

red1776 red1776, Omnipotent Ruler of the Universe, said:

The 4770 was a proof of concept exercise first and foremost, and a retail product secondly- hence the fact that the 4770 never appeared as a volume part.

I remember the RV 740 had more availability in Europe than the states like the 4860. So was the the RV740/4770 as a temp replacement for the 4830 a complete ruse?

dividebyzero dividebyzero, trainee n00b, said:

My understanding of the 4770 was that the model was first and foremost a debugging exercise for the 40nm process. Having a saleable model I think was an added bonus to a degree.

The fact that it's 5-series replacement appeared in retail/etail five months after the 4770's launch would tend to point to a pathfinder GPU for the HD 5xxx series rather than some pinnacle of the HD 4xxx series.

I think both the 4770 and the ubersalvage-part 4860 were both aimed more at secondary markets from memory- although if you can recall widespread availability in the U.S. then that would effectively put paid to that notion.

fpsgamerJR62 said:

@dividebyzero - thank you for your usual excellent technical discourse on the HD 4770

@red1776 - Sorry for the rather vague reference. It was the first thing that popped into my mind while reading the article about the HD 6790. It was the one card that I was not never able to get my hands on since it was always out of stock. After all, who wouldn't want a sub-$100 card which kicked major ass when benchmarked together with more expensive ATI and Nvidia cards.

red1776 red1776, Omnipotent Ruler of the Universe, said:

@red1776 - Sorry for the rather vague reference. It was the first thing that popped into my mind while reading the article about the HD 6790. It was the one card that I was not never able to get my hands on since it was always out of stock. After all, who wouldn't want a sub-$100 card which kicked major *** when benchmarked together with more expensive ATI and Nvidia cards.

aha, I know indeed. I attempted to purchase this card a couple of times myself and was unable to as well. (always sold out).

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