I've been thinking a lot about how ATI claims their x1800xt can beat the 7800gtx in any benchmark. I've heard rumors that ATI have increased the effectiveness of their pipelines 30% more than their previous generation. I've also read on the Inquirer that the x1800 is to be clocked at 625/1500. Since the x800xl was clocked at 400/1000 to compete with the 6800gt clocked at 350/1000, and still didn't win a whole lot of benchmarks, the GeForce 6 series cards had over 14% more efficiency per pipeline with it's GeForce 6 series over the x800 series. Putting those numbers together, the x1800 series should have a 14% increase per pipeline when compared to the GeForce 6 series. To compete with the x1800xt, a 6800gt or ultra would have to be clocked at 1112/1000, assuming that memory speed is as influencial as core speed in this hypothetical benchmark.

Anyway, looking at benchmarks between the 7800gtx and 6800ultra using Doom3 with highest settings and resolution I can find(Anandtech has 1 with Doom3 4xAA 2048x1536), I've estimated the 7800gtx to be only 181% as powerful as the 6800ultra. Since the 6800ultra has 16 pipelines and the 7800gtx has 24, the 7800gtx has a 21% gain in effectiveness per pipeline over the previous generation. To compete with a 7800gtx, a 6800gt or ultra would have to clocked at 778/1200, or 934/1000.

When comparing the reference 7800gtx with the reference x1800xt, it's 934 to 1112. In reference designs, the x1800xt has the lead. I've heard rumors that ATIs press conference reguarding the r520 featured a way for guests to benchmark the new cards against Nvidias competition card. To compete with the x1800xt, the 7800gtx would have to be clocked at 511/1200, and since some of the EVGA and XFX cards are clocked at 490/1300, the core would have to clocked at 472/1300 to compete. Apparently, the 7800gtx cards at the ATI conference are reference designes, and the x1800xt can't compete with the higher clocked 7800gtx models, and ATI knows it. To compete with the overclocked 7800gtx cards, x1800xt cards would have to be 675/1500, which it should be able to, since it's using a 90nm process and a huge dual slot cooler.

Then again, the 7800gtx can still overclock a little beyond 490/1300. In fact, without volt modding, you should be able to get 525/1400. That should compete with an x1800xt clocked at 780/1500. The memory on the r520 is supposed to be able to clock as high as 1600mhz, but no higher. If that's true, the r520 would only have to be clocked at 740/1600 to compete with the max clock on a 7800gtx. Both should be able to get the same benchmark results with a max overclock. Without the overclock, the x1800xt beats the reference designs of the 7800gtx, but not the higher clocked models. The x1800xt is to be priced at around $600, while the XFX overclocked 7800gtx is $500. Which would you rather have?

Then again, how many programs do you know that require as much memory bandwith as it requires in pixel power? If you ignore the memory speed, the 7800gtx has a theoretical pixel fill rate of 10320 million pixels per second with a 21% per pixel performance increase over the GeForce 6 series, while the x1800xt has 10,000 million pixels per second with a 14% per pixel performance increase over the GeForce6 series. The 7800gtx clearly has a large advantage. Though, if memory bandwith is a large factor, then the r520 has the clear advantage. Seriously, though, how many programs require a large amount of memory bandwith?