Santa Clara (CA) - This afternoon, senior Nvidia spokesperson Bryan Del Rizzo disputed the likelihood of reports emerging from Dell that the first Pentium D 900-series-based XPS 700 units being shipped do not contain Nvidia's top-of-the-line nForce 590 chipset as advertised, but instead a solution reached in Dell's own laboratories. "Based on my understanding," Del Rizzo told TG Daily this afternoon, "they are in fact using the Nvidia nForce 590 SLI MCP."

In recent weeks, according to customers awaiting shipments of their XPS 700 systems posting on Dell's user community forums, Dell customer service representatives have responded by e-mail saying that XPS 700 shipment delays were caused by a need to create an interim chipset solution for Dell's custom motherboard. One response cited on the forum - whose authenticity could not be positively verified - reads in part, "The XPS 700 will not have any of those capabilities because the chipset will not be a nforce 590 chip. It is a chip that is being built especially for us. It will be similar to the nforce 4 SLI chipset, but it will be a slimmed down version of that."

Citing the same language, a Dell XPS 700 customer recently wrote TG Daily to say she had discovered that the system actually includes "a limited version of the 590 southbridge combined with a 'slimmed down version of the nForce 4 northbridge.'" The customer added several of the 590's native features would be disabled.

Inside the Dell XPS 700. Passive heat sinks cool the northbridge and the southbridge, both of which Nvidia believes belong to the nForce 590 chipset.

"Frankly, I'm not sure what a slimmed down version of the nForce4 northbridge would be anyway," Del Rizzo told us. He conceded it is technically feasible for a customer in Dell's position to mix and match the systems platform processor (SPP, "northbridge") with the media and communications processor (MCP, "southbridge"). What would be feasible, he admitted, would be for Dell to have made the opposite choice: pairing the nForce 4 SLI X16 northbridge with the nForce 590 SLI southbridge. Mixing the opposite two components, he said, would be pointless. "The difference between the nForce 4 family and the nForce 5 family really lies in the MCP, not the SPP," he said. "There's really nothing to enable/disable on the SPP from an end user perspective, as it really is just a memory controller and CPU interface."

If the service rep's statement proves false, it would not be the first time. Other Dell customers have dissected this and other customer service excerpt gems in recent weeks, proving that the excuses they've provided - many of which are more calamitous than Dell's own official explanations - don't hold water technically.

But suppose the service rep got his bridges crossed, and meant to say "slimmed down southbridge?" "When it comes to the MCP features - support for dual GigE, teaming, nTune, etc. - it is up to Dell, and all of our other partners, to decide what features they want to offer to their customers," Nvidia's Del Rizzo told TG Daily. "We don't dictate what our partners offer to the end consumer, and many times they offer additional features (such as Firewire) that we do not integrate into our solutions."

Two weeks ago, Dell announced it had pegged a fault with the cooling assembly as the principal cause of the XPS 700 holdup. Since that time, more Pentium D-based units have shipped, according to customers who report having received them. Meanwhile, other customers who opted to upgrade to a Core 2 Duo- or Core 2 Extreme-based system report estimated delivery dates as late as 17 October.