After covering the budget and midrange sectors of the DIY PC market, as well as pre-built desktops and laptops, today we have a guide outlining mainstream high-end builds. Saying the computers outlined in this guide are capable is an understatement—these are seriously powerful (and spendy!) systems. These rigs check out around $2000, at the top of the mainstream market. Each of them will be able to serve their owners well for years to come.

We start with a fancy mini-ITX HTPC that has lots of room for a huge media library and is capable of encoding videos quickly, followed by an impressive gaming box, and finish with a powerful workstation featuring Intel's latest CPU architecture, Sandy Bridge-E.

In our first run with the Alienware M18x, we sat down and took a look at the notebook itself along with NVIDIA's current top shelf mobile graphics part, the GeForce GTX 580M. We came away from the experience with mixed impressions of the M18x itself, a notebook that is by all means incredibly powerful but also seems to lose a lot of the balance that made the M17x R3 so desirable. On the other hand, the GeForce GTX 580M wound up being the fastest mobile GPU we'd yet tested, made only more formidable through the SLI configuration the M18x enables.

Today, Alienware has graciously provided us with the second half of the current top shelf performance equation in the form of a near-identically configured M18x, this time with two AMD Radeon HD 6990Ms in CrossFire. We'll also take a look at the Intel Core i7-2920XM's stock performance and compare it against the overclocked settings Alienware allows you to configure it with.

It's easy to build a powerful desktop if you take a big, beefy enclosure like SilverStone's FT-02 or the Thermaltake Level 10 GT and just fill it with the highest performance parts on the market, overclock them, and call it a day—and certainly we've seen our share of those. Taking all of that raw performance and shrinking it into a MicroATX case can be a little more difficult, though, especially when you're dissipating a cumulative TDP of at least 730 watts. Yet when we saw that AVADirect had produced another compact but incredibly high performance gaming desktop, we had to take a look. Gulftown may be on its way to bed soon with the advent of Sandy Bridge-E, but let's see if we can't give it one last hurrah in the process.

It’s been quite a while since we’ve looked at triple-GPU CrossFire and SLI performance – or for that matter looking at GPU scaling in-depth. While NVIDIA in particular likes to promote multi-GPU configurations as a price-practical upgrade path, such configurations are still almost always the domain of the high-end gamer. At $700 we have the recently launched GeForce GTX 590 and Radeon HD 6990, dual-GPU cards whose existence is hedged on how well games will scale across multiple GPUs. Beyond that we move into the truly exotic: triple-GPU configurations using three single-GPU cards, and quad-GPU configurations using a pair of the aforementioned dual-GPU cards. If you have the money, NVIDIA and AMD will gladly sell you upwards of $1500 in video cards to maximize your gaming performance.

Today we’re going to be looking at the state of GPU scaling for dual-GPU and triple-GPU configurations. While we accept that multi-GPU scaling will rarely (if ever) hit 100%, just how much performance are you getting out of that 2^nd or 3^rd GPU versus how much money you’ve put into it? That’s the question we’re going to try to answer today.