Ever wondered whether all those system tray programs lower your FPS? 

When I was younger, my low-budget PC struggled to run most games, so I made it a habit to shut down any unused background programs, virus scanners, and services before every gaming session.

Nowadays, I'm older, have a real job, and am fortunate enough to be able to spend more money on my beloved hobby. With a high-end CPU and two high-end GPUs in SLI, I have the luxury of being able to just boot up a game, put all settings to max, turn on 3Dvision, and enjoy what is usually a smooth, sumptuous gaming experience. But I started wondering: was I hurting my performance by forsaking this old habit? Could I still get a noticeable boost by shutting off a few programs before I launch a game? 

Conventional wisdom says that 'No, those days are over': today's CPUs are much better at multi-tasking, so leaving background programs running shouldn't impact gaming in any serious way. Still, I decided to find out for myself, if only for peace of mind.

So, you've decided to join the true PC Gaming Master Race and get 3Dvision. Nice one! Once you've experienced the exquisite immersion that comes from gaming in proper 3D, you'll find it hard to ever go back. But 3Dvision comes with a performance cost, and you're wondering how your PC will handle it. How much 3Dvision affects your FPS varies game by game, but there are some rules of thumb.

In 3Dvision, the GPU needs to pump out twice the frames as in 2D (one for each eye). Based on this, 3Dvision users sometimes make two claims:

• Claim #1: Turning on 3Dvision in a game will generally halve the FPS
• Claim #2: 3Dvision and SLI are a match made in heaven, since the former requires two [similar] frames per eye, and the latter gives you two [similar] GPUs with which to render them.

Intuitively, these claims sound fair enough, but I decided to do some testing and find out for sure.

Whether it's the littered newspapers that gracefully catch the wind under Batman's feet in the Arkham games, chunks of wall crumbling under gunfire in Metro: Last Light, or the technicolor mayhem of a singularity grenade in Borderlands 2, PhysX can add a great deal of dynamism to a game. Unfortunately, it usually comes with a substantial (and often underestimated) performance cost - not just in the form of a FPS hit, but also microstuttering or downright freezes.

We can counteract this performance penalty by dedicating a secondary video card exclusively to PhysX, but how much does it actually help? I've long known the benefits of a dedicated PhysX card from personal experience, but until now I'd never tested them systematically.