The troublesome birth of ATI's R520 "Fudo"

IT TOOK ATI three years to make its R520 - codenamed Fudo - happen. This chip is the first revolutionary design since way back when the company introduced the R300, subsequently the Radeon 9700PRO.

The new card features many new things but compared to a Geforce 7800GTX it won't offer much more. ATI offers some nice features such as HDR and SM 3.0 that were already there. ATI now supports Shader model 3.0 and claims that its implementation is much better than Nvidia's. We know that Nvidia had some issues with branching and ATI says it solved this issue and made its Shader model 3.0 more efficient.

This is the first chip made in 90 nanometre and ATI had many issues with it. The R520 was first taped out in November 2004, almost a year ago and ATI had it up and running even back than. But switching from 110 nanometre to 90 is not an easy thing to do so ATI experienced many troubles doing it.

The key problem that ATI had with the R520 was inability to clock the chip at speeds over 500MHz. On a 90 nanometre process, you should easily hit close to 700MHz target with air cooling. When you overclock with dry ice this chip can reach 900+ MHz. ATI had a "current leak" problem as it had decent yields with 500MHz clocked chips. That was a physical problem, where transistors were getting unstable at any clock higher than 500MHz. You will know these 500MHz cards and actually can buy them as Radeon X1800XL, R520XL.

We know that certain developers got their first R520 cards back in April but working at 490MHz - till recently that was the highest that company could reach. The card is a nifty performer even at those speeds but if you clock it at 625/1500MHz you can expect numbers that can give run G70, Geforce 7800 GTX, a run for its money.

It took ATI seven months to get aropund to addressing the current leakage problem. ATI engineers didn't predict the transistor behaviour and the problem was between transistors and the interconnections on the chip.

But, once the problem was addressed, ATI says it only took 24 hours to fix and all it needed to do was to add another metal layer. Once that happened ATI started to celebrate and the guy that solved the problem got a huge bonus for its efforts. He can probably be known as Fudo's saviour.

Yields are now very good and you should expect to see a massive quantity of X1800XT on shelves in about four weeks.

Yes, it's late; yes, was delayed and, yes, it's not available instantly but, still, we liked what we saw.

If you still haven't bought a GTX card then it might be a good idea to wait for a R520-based X1800XT or check out the even more affordable X1800XL cards available now. The R520XL, named Radeon X1800XL and clocked at 500MHz core and 1000MHz memory is on a par with Nvidia's Geforce 7800GT.

We should mention ATI's support for dual transmitter. And its ability to support two MAC 30 inch displays with 2650x1600 resolution really caught Nvidia off guard. Avivo is definitely something that might switch you on to ATI as Nvidia simply doesn't have anything like it.

Nvidia is now under pressure and just released its release 81 driver. It also has a hardware answer called G71 which is a 90 nanometre G70 (we should say NV47). This chip can and will hit some higher clocks and will give the R520XT (Radeon X1800XT) a run for its money, big time. But that leads us to another round of this graphic boxing match as ATI will then have its chip codenamed R580. We will be there to watch that episode.

Several ATI people including some of the VPs told us to expect massive availability of Radeon X1800XT before Thanksgiving and we have every reason to believe them. µ