Most computer dealers cut costs by using less costly OEM versions of well-known parts if they are branded like an ATi or nVIDIA video adapter and hidden components that buyers seldom ask about or notice, such as motherboards, optical and hard drives, power supplies, and etc.

OEM parts may be similar retail models, varying only in packaging. But even if the parts are the same, there are frequent significant differences. Part sellers normally don’t support OEM versions directly, for instance, instead considering you to the system seller. If that system seller goes out of business, you’re out of luck, as the component manufactures provides no warranty to end users. Even if the maker does support OEM, the warranty offered is of shorter period on OEM parts say 30-90 days. The products themselves also vary significantly between OEM and retail-boxed versions. Many PC sellers often use downgraded versions of branded products, for instance, an OEM video adapter having same or a similar name as the retail-boxed product but running at a lower clock rate. This allows PC manufacturers to pay reasonably less for parts and still gain the cachet from using the name-brand product.

The case of scenario is even worse in the case of hidden parts. We have popped the exterior on scores of consumer-grade PCs in past years, and it never ceases to surprise us just how cheaply they’re made. For instance, not a one of them had a power supply that we would even recommend using in one of our own systems. They’re packed with no-name motherboards, generic memory, the cheapest optical drives available, and so on. Even the cables are often of poor quality. After all, why pay a more for a normal cable? Considering reliability, we recommend a consumer-grade PC a trouble waiting to happen.

Every commercial PCs are poorly built. Most business-class systems by IBM and other high-end sellers are well built with high-quality part and high build quality. Obliviously, a business-class system is expensive than a consumer-grade system.