Unlocking the GeForce 6800

Timmus writes "Firingsquad is running a story on how to unlock all 16 pipelines in nVidia's GeForce 6800. By default the card only ships with 12 pixel pipelines enabled, but with a tool and a few mouse clicks, the card can be unlocked to run with all 16 pipes. Performance improvements are seen everywhere, so it's a pretty nice free upgrade. These cards are currently selling for $200 online, so a 16-pipe GeForce 6800 delivers great bang for the buck."

Comments

Re:I hate to trolll but....

[iminplaya]

...if the card worked 100% fine with 16 pipelines they would have sold it that way.

A lot of equipment is sold with diminished capacity to cover up possible defects.

Re:Disabled Hardware??

[Azreal]

Usually the 4 pipes are locked for couple of reasons. Early on, when the card first came out, demand was fairly high across the board for 6800-6800ultra's and production was fairly low. As a result, some 6800's were basically 6800gt's with pipes locked, or in the rare instance of like the evga 6800limited edition (not to be confused with 6800LE), it was a 6800ultra clocked down or pipe locked...I forget. Now, production has basically met demand and the pipes are usually locked because of defects in the manufacturing process to said pipes. If a single pipe is "broken" it can't be sold as a 6800gt so 3 other pipes are locked to make it a 6800 vanilla. You can unlock all 4 pipes but you'll usually see artifacting. If you can figure out exactly which pipe or pipes are broken, you can re-lock those ones and have a better performing 6800..but not quite a 6800gt.

Re:Disabled Hardware??

[LarsG]

Why would the PCI-E version only ship with 12 pipelines, hrm?

It is a question of manufacturing yields and economics.

When the NV40 was introduced, they were manufactured using a brand new process. nVidia expected a low yield, leading to many parts with some vertex/pixel pipelines botched. So, instead of manufacturing two different cores - one with 12 pipelines for the mid-end and one with 16 pipelines for high-end, and then having to throw out all chips with defects - they instead only manufactured 16 pipeline cores, and chips with a certain number of defects could be down-graded to 12 pipelines. In effect increasing the number of chips that could be sold instead of thrown away.

As the manufacturing process matures, the number of chips with no defects increases. But since there are only so many people that want to buy a high-end chip, nVidia has to deliberately downgrade chips to fill the market demand for mid-end graphics cards.

Now, a 16 pipeline core is larger than a 12 pipeline core, meaning fewer chips per wafer. Once the manufacturing process is good enough, the required number of working high- and mid-end chips can be manufactured cheaper by using two different cores. Evidently, that line was reached by the time the PCI-E versions of the 6800 were introduced.

Note that this is quite common in the semiconductor industry.

Selling chips with certain faults as lower performance (or having redundant functional units on the core), decreasing the number of chips going to the trash. 80486DX with faulty math coprocessor were sold as 486SX. RAM chips often have a few redundant memory banks.

Deliberately down-clocking/-grading chips to fill market demand. Celerons based on a mature core / manufacturing process are usually very good overclockers.