Morgan Stanley says the gaming performance of Nvidia's latest graphics card is below its expectations.

In August, Nvidia announced its new eighth-generation Turing graphics architecture. Technology media outlets published reviews on the company's first gaming cards based on the new chips Wednesday morning.

"As review embargos broke for the new gaming products, performance improvements in older games is not the leap we had initially hoped for," Morgan Stanley analyst Joseph Moore said in a note to clients on Thursday. "Performance boost on older games that do not incorporate advanced features is somewhat below our initial expectations, and review recommendations are mixed given higher price points."

Nvidia shares closed down 2.1 percent Thursday.

Moore noted that Nvidia's new RTX 2080 card performed only 3 percent better than the previous generation's 1080Ti card at 4K resolutions.

"We are surprised that the 2080 is only slightly better than the 1080ti, which has been available for over a year and is slightly less expensive," he said. "With higher clock speeds, higher core count, and 40% higher memory bandwidth, we had expected a bigger boost."

As a result he expects the adoption of Nvidia's new products to be "slower" and doesn't expect "much upside" from the company's gaming business in its next two financial quarters.

Despite the disappointment, Moore reiterated his overweight rating and $273 price target for Nvidia shares due to the company's strong long-term technology position.

Correction: The correct name of the new card is RTX 2080.

— CNBC's Michael Bloom contributed to this story.