Last week, Valve released their very popular Steam client for Mac OS X. This included a list of games that were ported over to the OS including one of my personal favorites: Portal. However, in testing, Steam looks to have some serious issues on the Mac platform.

Anandtech, one of the best tech sites around, showcased the new Steam in an article entitled Mac OS X Portal Performance. In it, Ryan says "There’s clearly a difference in IQ between the Windows and Mac OS X versions of Portal, and it’s not in the Mac’s favor." He's referring to washed out colors, lighting effects not being rendered as well, and an overall lack of fidelity in the Mac client. But that's only the tip of the iceberg.

When it came down to performance, Ryan tested with a Geforce GTX 285 (as the GTX 400 series are unsupported on Mac OS, as is SLI which would be needed to make a GTX 295 work) on a Core i7 CPU and motherboard, a very similar configuration to Apple's $4000 Mac Pro specs or a $2200 Odin configuration. We all knew that OpenGL would be a little slower than DirectX, but how much?

Wow! A $4,000 Mac can hardly run Portal on a 30" LCD. Of course, you can remedy that by installing Windows on the machine and running it there, but why would you want to own a Mac Pro then? Scarily enough, these numbers make it appear that a current iMac will have a lot of trouble running at native resolution as well, as an HD 4670 is simply no where near this level of performance, and the HD 4850 is probably enough to run comfortably at 1920x1200, but certainly not at 2560x1440.

So, while we now see that even ported applications that have been rewritten for Mac OS can't run as well as they do in Windows, what about native applications on both platforms? Luckily, Phoronix recently ran a gauntlet of tests on all three major OS's: Windows, Mac and Linux. Let's see how that turned out:

These results can be seen on page three of their report, but what we see with even Mac Mini hardware is that Windows is the clear winner, maintaining good playability all the way to 1080p resolution on NVIDIA hardware. Mac OS X and Linux are clearly struggling to keep up past 1280x1024.

What we have to ask, with OpenGL becoming more and more important, is what will performance with Creative Suite 5 look like? We know that 64-bit Photoshop CS4 ran faster than it's 32-bit counterpart for Mac OS, but what about the rest of the new suite? Unfortunately, we don't have any numbers at the moment, but I'm in the process of making some. I fully expect to see CS5 run substantially faster on Windows than Mac OS if the above number have anything to do with it.

It's nice to see Windows back in the driver seat after all these years, and with performance boosting techniques like multi-core support in DirectX 11, we'll continue to see PC take over the wins in gaming performance.