Strong gains from FTSE 250 chip designer Imagination Technologies gave the technology sector a lift on Wednesday, with shares rebounding after their recent weakness.The stock slumped to a 52-week and three-year low of 235.1p on July 31st on concerns over market share losses, but has risen strongly in the two weeks since, jumping a further 14.3% to 284p today.The recent performance is likely to have something to do with share-price gains from US tech giant and Imagination customer Apple - both stocks have been strongly correlated historically, albeit less so in recent years - which beat expectations with its quarterly results at the end of July, reporting strong sales of its iPhones.Meanwhile, as the market gears up for the launch of the next iPhone model on September 10th, Apple has again been in the spotlight in recent days after billionaire investor Carl Icahn revealed he has built up a "large" stake in the company and said its shares are "extremely undervalued". He also called for the firm to increase its share buyback and has had conversations with Chief Executive Tim Cook. Apple's share price has surged by nearly 10% over the past three days alone.Imagination's UK-listed peer ARM Holdings, by far the largest UK stock in the tech sector with a market cap of nearly £12.5bn, was also in demand today trading 0.5% higher at 896p. ARM is also a supplier to Apple.Other tech stocks were performing well today, including Nano Amino Technologies, CSR and Sepura.Concurrent Technologies was also higher, rebounding after disappointing the market earlier in the week with a trading update. The company, which specialises in embedded computer products for markets such as defence, aerospace and telecoms, said on Monday that it had problems in emerging markets due to the government's export licencing system for products containing encryption technology. This was having a "negative impact on the company's financial performance in the short term", it said.Top performing sectors so far todayIndustrial Metals & Mining 1,494.81 +1.07%Electronic & Electrical Equipment 4,182.71 +1.00%Technology Hardware & Equipment 1,075.47 +0.93%Personal Goods 25,443.01 +0.89%Industrial Engineering 10,142.88 +0.82%Bottom performing sectors so far todayAutomobiles & Parts 8,134.13 -1.50%Fixed Line Telecommunications 3,755.00 -1.18%Mobile Telecommunications 4,574.96 -0.88%Construction & Materials 3,999.70 -0.85%Gas, Water & Multiutilities 5,779.23 -0.75%BC