Silicon Graphics International Corp. (SGI; formerly Rackable Systems, Inc.) was an American manufacturer of computer hardware and software, including high-performance computing solutions, x86-based servers for datacenter deployment, and visualization products. It was founded as Rackable Systems in 1999.

On November 1, 2016, Hewlett Packard Enterprise completed its acquisition of SGI for $275 million.

In 2006, Rackable announced it had signed an agreement to acquire Terrascale Technologies, Inc.

On April 1, 2009, Rackable announced an agreement to acquire Silicon Graphics, Inc. for $25 million. The sale, ultimately for $42.5 million, was finalized on May 11, 2009; at the same time, Rackable announced their adoption of "SGI" as their global name and brand. The following week, the company changed their NASDAQ stock ticker symbol from "RACK" to "SGI".

The "new" SGI began with two main product lines: servers and storage continuing from the original Rackable Systems; and servers, storage, visualization and professional services acquired from Silicon Graphics, Inc. At the time of the acquisition's completion, SGI said that they anticipated the survival of the majority of the two companies' product lines, although some consolidation was likely in areas of high overlap between products.

In 2010, SGI announced the purchase of all the assets and assumed a limited amount of liabilities of COPAN Systems. COPAN was a provider of storage archive products for real-time access to long-term persistent data. COPAN products were offered as part of the SGI storage line.

In 2011, SGI acquired all outstanding shares of SGI Japan, Ltd. The same year, the company announced the acquisition of OpenCFD Ltd. In December, the company announced Mark J. Barrenechea's resignation as president, chief executive officer and member of the Board of Directors. Mark was reported to join Open Text Corporation. Shortly thereafter, it was announced that Barrenechea had agreed to continue to serve on the SGI board.

In February 2012, it was announced that Jorge Luis Titinger would become SGI's president and chief executive officer.

In 2013 SGI acquired FileTek, Inc.

On August 11, 2016, it was announced that Hewlett Packard Enterprise would acquire SGI for $7.75 per share in cash, a transaction valued at approximately $275 million, net of cash and debt. The deal was completed on November 1, 2016.