Our sample came with a Core 2 Duo E6600 processor which operated at 2.40GHz by default. When overclocked it operated at 2.88GHz, making it a serious mobile processor.
It is worth noting that while the C90S does support the Core 2 Extreme X6800, the overclocking mode is not available with this processor. Asus points out that the thermal load would be far too high in this situation. We can certainly believe this as we saw the cooling struggling with the overclocked E6600. At the stock 2.4GHz our laptop was quite warm to touch already.
Interestingly, the C90S motherboard is equipped with the older Intel 945G chipset, which uses the ICH7 southbridge. This means that the cooler 45nm Core 2 processors are not supported by the C90S, limiting its upgrade path lifespan. We can attribute this decision to the fact that Asus started working on this design almost two years ago, but it didn't make it to retail until late last year. We hope that there will be a future version of this laptop that can offer improved processor support. We are sure it wouldn't take much beyond what we already have on the C90S.
Another limiting factor of the C90S involves the Nvidia Mobile PCI Express module, which supports up to a GeForce 8600M GT with either 256MB or 512MB. The GeForce 8600 series was never great for gaming, and the mobile version is even worse. Had the C90S offered the ability to install a GeForce 8800M GTS or GTX, it would have been a serious threat to desktop gaming computers.
The C90S can support up to 3GB of DDR2 memory using dual SO-DIMM slots. This memory can only operate at 667MHz, though in the past we have found that there is little performance difference between DDR2-667 and DDR2-800 memory on the Core 2 platform. The C90S generally comes with hard drives ranging from 80GB to 160GB with a spindle speeds of either 5400 RPM or 7200 RPM. Of course, you could add a much bigger hard drive if you wanted to. Our sample included a 160GB Serial ATA Seagate Momentus 5400.3 drive.
Overall, the specifications of the ASUS C90S laptop are impressive and certainly place it in the high-end mobile market segment. However, keep in mind that the C90S can come in a number of variations that include different processors, graphics cards, less or more memory, and a smaller yet possibly faster hard drive.