Nvidia on Wednesday released a new set of WHQL Graphics drivers that allow 4-way SLI configurations with GeForce GTX 480 or GeForce GTX 470 GPUs.

The latest WHQL-certified Nvidia Forceware drivers version 197.55 for Windows Vista and Windows 7 operating systems enable 4-way SLI with GeForce GTX 480 or GeForce GTX 470 graphics boards for the first time. Until now, Nvidia only allowed 4-way multi-GPU mode to work on two dual-chip graphics boards. The same applies for AMD/ATI, although both companies enabled 3-way multi-GPU modes for single-chip solutions.

A 4-way SLI configuration with GeForce GTX 480 GPUs could offers tremendous amount of processing power, outperforming AMD's oferings based on ATI Radeon HD 5870 accelerators.

However, the cost of GeForce GTX 480 graphics cards varies from $1500 to $2000, which is way to much for the casual gamer to spend. Adding to this the cost for a high-end motherboard equipped with four PCI Express x16 slots as well as for a huge PSU to power these quad-GPU set up results to a way too high expense.

If you are still needing this driver, you can download it here.

Low Yields For Fermi GPUs

In related news, its seems that Nvidia is hit by low yields for the Fermi chips, which are reportedly between 20% and 30%. According to the analysts, Nvidia's Fermi graphics processor is not ramping well and could face further delays.

Needham & Co. dropped its rating to Hold from Strong Buy and recommended Nvidia's investors "sell into any near term strength."

"We are downgrading NVIDIA to a Hold and removing our 12-month price target (was $22) after a series of channel checks indicating that Fermi is not ramping well and there could be further product delays. Based on our findings, NVIDIA has very limited supply of Fermi desktop/notebook parts and yields remain poor at around 20-30% .." said analysts from Needham & Company.

Although Nvidia has already officially released its Fermi-based GeForce GTX 470 and GTX 480 graphics boards on the 12th of April, their availability remains a problem. A quick search in various stores online list both these graphics cards as "out of stock" and and where it is in stock, they costs much more than Nvidia's recommended price.

Meanwhile, Nvidia's rival AMD has officially announced that it had shipped over two milion DirectX 11 graphics cards.