My black MacBook spent its day yesterday in the PC World Test Center (Digit's sister title), in the capable hands of development analyst Thomas Luong, and I'm happy to say that we now have performance data for it.

Our performance benchmark, WorldBench 5, is designed to test Windows-based PCs -- so we prepped the MacBook by turning it into one. We installed Boot Camp and Windows XP Home in a FAT32 partition, then ran WorldBench and its battery of real-world tests using applications like Microsoft Office, Photoshop, and WinZip.

How'd it do? Quite well for a notebook with a fast CPU (Intel's 2GHz Core Duo) but relatively skimpy RAM (512MB) and integrated graphics that steal their RAM from the main memory. In fact, the MacBook's WorldBench score is 88 is faster than four of the five models on our current All-Purpose Laptops Top 5.

Our #1 all-purpose laptop at the moment, Dell's Inspiron E1505, has a WorldBench score of 82, close enough to the MacBook's 88 that you probably wouldn't notice a difference. The Inspiron has a slower version of the Core Duo chip, but it has discrete graphics (vs. the MacBook's integrated graphics) and we tested it with 1GB of RAM (twice as much as the MacBook's 512MB).

The only other Intel-based Mac we've run WorldBench on so far is a desktop: the 20-inch iMac. Its WorldBench score of 96 handily beats the MacBook, which makes sense given that it had the same 2GHz CPU but 1GB of RAM and discrete graphics.

Thomas also ran some of our gaming-based graphics tests on the MacBook. The results won't set any serious gamer's heart aflutter, which is neither a surprise nor a great loss, since no serious gamer would consider a notebook with integrated graphics in the first place. It managed 4.5 frames per second in our Doom 3 test (at 1024-x-768 without anti-aliasing); at 48 frames per second, the iMac was more than ten times as fast here.

WorldBench 5 is a Windows-based benchmark, so it can't tell us how fast the MacBook is compared to earlier G4-based Mac notebooks that couldn't run Windows. But our colleague Jim Galbraith of Macworld ran Macworld's OS X-based benchmarks on the MacBook; he didn't find the 4X-to-5X boost bandied about in Apple advertising, but the MacBook was much faster than G4-based Mac laptops in most of his tests. (The MacBook Pro was faster still, helping it to deserve that "Pro" moniker.)

The bottom line here? If you're planning to buy a notebook and top-notch performance (especially for games) is a primary goal, the MacBook probably isn't going to make sense, because no notebook with integrated graphics will.

But the MacBook's XP performance is right in the zone for general-purpose notebooks. Which is good news if you're intrigued by it, but are worried that a machine designed to run Mac OS can't possibly do a decent job at running Windows XP. The MacBook can, and does.