The Dow Jones Industrial Average (DJINDICES:^DJI) had added more than 56 points as of 11:30 a.m. EDT. Cisco (NASDAQ:CSCO) was one of the index's top performers, while tech stocks NVIDIA (NASDAQ:NVDA) and Marvell Technology (NASDAQ:MRVL) also moved higher.

ISM Manufacturing PMI comes in lower than expected
Perhaps limiting the Dow Jones' gain on Tuesday, the Institute for Supply Management manufacturing purchasing managers' index reading of 53.7 missed the even 54 that economists had anticipated. This suggests the U.S. economy may be weaker than believed.

A weaker economy could weigh on stocks, but it should be noted that any reading over 50 indicates expansion -- the manufacturing sector is growing, just not growing as fast as anticipated.

Source: Wiki Commons.

Cisco rises ahead of presentation
Cisco shares were up 1.6% early on Tuesday, ahead of CTO Padmasree Warrior's presentation at the annual Tech Transformation Summit, scheduled for 10:30 a.m. PDT. Warrior's comments from that presentation could elevate shares further.

Also on Tuesday, Cisco announced that it was expanding its open IP Cameras platform to include better video storage features, and has implemented a feature to allow for push-to-talk interaction. The announcement didn't appear to be a major upgrade to Cisco's current business, but could help fuel continued speculation that Cisco will be a winner in the coming "Internet of Things" revolution.

NVIDIA moves higher on analyst upgrade
NVIDIA shares rose 4% early in the session. The source of the rally was likely an upgrade from JMP Securities analyst Alex Gauna, who raised his rating on the chipmaker to outperform on Tuesday.

JMP Securities was impressed with NVIDIA's growing focus on the cloud and the automotive industry, among other initiatives. NVIDIA's new products could deliver earnings upside in the coming quarters.

Marvell Technology surges on damages
Marvell Technology shares rose more than 3.8% early on Tuesday after a judge ruled that the company should pay Carnegie Mellon University $1.54 billion for violating patents.

Carnegie Mellon had asked for triple that amount of damages, but the judge denied the request. A fine of $1.54 billion is no doubt hefty, particularly for a company with a market cap just over $8 billion -- but it's obviously better than triple damages.