We find out which hardware upgrades do the most cost-effective job of turbocharging your PC.

You want a faster system? Put faster parts in it. That's the simple an­­swer to a question that every PC owner asks from time to time. But replacement parts aren't free, and cash-strapped computer enthusiasts know that the key is to put their money where it counts most.

That's why we sought to identify which upgrades give PCs the best and most cost effective performance upgrades.

First, we separated our benchmark tests into two components: general system tasks (including office applications, photo editing, and movie encoding), and gaming. Then we divided our up­­grades into four categories: CPU, RAM, hard drive, and graphics board.

We selected two primary test systems to represent the kinds of desktop PCs that users are likely to want to overhaul with hardware upgrades: a three-year-old machine with a 3.4GHz Pentium D processor, 2GB of RAM, a 500GB hard drive, and a GeForce 8800GT graphics card; and a one-year old PC with a 2.8­GHz Core i7 CPU, 4GB of RAM, a 1TB hard drive, and an ATI HD 5670 graphics card. We then ran tests on the systems using various combinations of the above upgrades to determine which configurations yielded the best return on in­­vest­ment. The results for individual PCs will vary greatly, but the data supports some general conclusions about which up­­grades make the most sense--and our recommendations may surprise you.

Upgrading the CPU

Bumping our three-year old machine's processor from a Pentium D to a Core 2-class chip yielded instant and obvious performance improvements across the board. Moving to a 2.67GHz Core 2 Quad prompted a 36.8 percent jump in performance on general apps. Using an older 3.0GHz Core 2 Duo was even more effective, with a boost of 52.6 percent - probably due to the speedier frontside bus in the Core 2 Duo over the Core 2 Quad. Graphics performance improved even more for both upgrades.

Best of all, our CPU upgrades were affordable. The Core 2 Duo upgrade rated as one of our best values in the entire study, costing a mere $2.91 (£1.78) for each percentage point of general performance improvement.

Upgrading RAM

Conventional wisdom has always held that upgrading your system's RAM will give it an instant boost. The upgrade is easy to perform, and it makes sense because RAM is cheap. But if your PC already has even a moderate amount of RAM, you likely won't see much of a speed increase from adding more. For example, when we bumped our 2GB system up to 4GB, we got a paltry 1.3 percent improvement on general apps and virtually no improvement on games. Similarly, our year-old PC's performance im­­proved by just three percent when we moved from 4GB of RAM to 8GB. The limited benefit that the up­­grade provided in our tests made investing in more memory almost pointless.

NEXT PAGE: Upgrading the hard drive

  1. Turbocharge your PC cost effectively
  2. Upgrading the hard drive