Shares of Apple ( AAPL) closed regular trading up nearly 4% on Monday after the company announced that it is upping the performance -- and dropping the price -- of one of its lines of notebook computers. On its high-end PowerBook notebooks, the company is now offering PowerPC G4 chips running at 1.5GHz or 1.67 GHz, compared with the previous range of 1.33 GHz to 1.5 GHz. Meanwhile, the company dropped prices on its PowerBook line by up to $200. Apple's announcement came early on Monday. At the bell, the company's stock was up $2.92, or 4%, to $76.90. The company is likely looking to juice sales of its PowerBook lineup. While overall sales of Apple's computers jumped 30% year over year in its most recent quarter , revenue from its PowerBook line fell 23%. Monday's announcement marked the first time Apple has updated its PowerBook line since last April. Apple is now offering its top-of-the-line PowerBook for about $2,700. In addition to the 1.67 GHz G4 processor, the device includes a 17-inch display, a 100GB hard drive, 512MB of SDRAM and an ATI graphics card with 128MB of video RAM. The company sold the previous iteration of that model, which had a 1.5 GHz processor and an 80GB hard drive, for about $2,800. With a base price of about $1,500, the entry-level PowerBook now includes a 1.5 GHz processor, 512MB of SDRAM, a 12-inch screen and a 60GB hard drive. Previously, Apple's starter PowerBook cost about $1,600 and included a 1.33 GHz processor and only 256MB of RAM.