HP has been known for innovation in operating systems, processors, design, and features like HD-DVD. This time it's leading the green pack. The HP Compaq dc7800 Ultra-Slim Desktop ($1,206 direct, $1,470 with 19-inch widescreen LCD monitor) is one of the innovators in the latest wave of energy-efficient yet capable desktops PCs. While the previous generation of green PCs was hampered by slower CPUs and components like notebook-class hard drives, the newest models run full-powered CPUs, and their more energy-efficient power supplies no longer compromise performance. The dc7800 should be on your shopping list if you're looking for an all-business PC that can save your company money in operating costs.

The dc7800 is available in three basic models: Convertible Minitower, Small Form Factor, and the Ultra-Slim Desktop reviewed here. Like the Dell OptiPlex 755, the HP dc7800 is meant to be a mainline business model with a common platform (motherboard chipset, CPU, and graphics choices) that can be housed in several model types. The Ultra-Slim desktop eschews internal expansion for overall compactness, yet without skimping on components. The dc7800 I reviewed has a 2.66-GHz Core 2 Duo E6750, along with a compact, notebook-class, dual-layer DVD burner and eight USB ports. You give up internal PCI/PCIe expansion in the ultra-slim model, but the system does have both VGA and DVI ports connected to the integrated Intel GMA 3100 graphics. Since the model is so compact, the power supply is external, but at least it's 80 PLUS certified—meaning that the power supply is designed to use power-saving technologies and is 80 percent efficient, as opposed to the 30 to 60 percent efficiency of standard AC-to-DC power supplies).

The dc7800's energy usage is quite impressive and befits its Energy Star 4.0 certification: It consumes 2 watts in S3 sleep mode, 1W when turned off, and only 33W at idle (but operating). Its power usage at "full blast" was a smidge higher than that of other green desktop PCs: 73W average (no doubt due to its full-power E6750 processor) but still energy efficient compared with more multimedia-oriented consumer PCs and business-oriented workstations. With more memory and drive space, the dc7800 could rival the more expensive and power-hungry 2D workstations in HP's xw-series.

The dc7800 is EPEAT Silver-certified, one step short of GOLD. Its chassis and components passed all of EPEAT's criteria for reduction/elimination of environmentally sensitive materials: Reduction of Hazardous Substances (RoHS), no cadmium, PVC-free panels; design for end of life (90 percent recyclable, marked recyclable parts), and product longevity (modular design, ease of upgrades, available three-year warranty). The dc7800 also passes the "3 R's test" in that it's designed to be reused and repaired, reduces the release of harmful substances into the environment, and can be recycled when it's finally obsolete. HP, like the other PC makers, has a few things to work on, like the use of more post-consumer recycled materials in manufacturing and the auditing of recycling vendors, but it's certainly an improvement in corporate attitude and practice over the "disposable business PCs" of the 1980s and 1990s.

The dc7800 has one of the faster processors I've seen in a business machine lately, but it still isn't the fastest overall on the SYSmark 2007 Preview benchmark tests, at least not as shipped to PC Magazine. The system's relatively meager 1GB of memory meant that performance lagged behind those with 2GB of memory on tests that involve multitasking. Though it still achieved good scores, the dc7800 lagged on Electronic Learning (86), Video Creation (84), Office Productivity (100) and Overall (101). By contrast, however, it did blow the others out of the water on 3D Modeling (142), thanks to its speedy dual-core E6750 processor. Give this system more memory, a $110-to-$150 upgrade, and you'll have a speed demon on your hands.

The dc7800 is just a smidge larger than the recently Lenovo ThinkCentre a61e, but it has both VGA and DVI ports—important since most companies have both types of monitors floating around. The a61e is quite a bit less expensive, making it the choice for those on a budget. The Dell OptiPlex 755 has a more comprehensive EPEAT Gold rating and is also offered in another model (a "true" desktop chassis). The OptiPlex is ever so slightly cheaper than the dc7800, yet it one-ups it with a dual 160GB hard drive with data backup, space for PCI and PCIe expansion cards, and an internal power supply. Though the dc7800 puts on a good show, the OptiPlex outshines it in price, performance, and features.

As our system was configured, there's a lot to like about the HP Compaq dc7800 Ultra Slim desktop. If you decide to get one, make sure you check the "Energy Star 4.0" configuration(s) to get the green models. Systems like the dc7800 can help save your company some money on its power bill. And you might possibly garner some good karma (future goodwill) by buying computers designed to give you a long service life and a good end-of-life, as the PC can be easily recycled down the road.

Check out the HP Compaq dc7800 Ultra-Slim Desktop's test scores.