Do USB devices snitch CPU cycles?

[cage]

Hi all, quick question: Does anyone here know how much more work the cpu has to do while maintainin g links with USB devices? I'm asking this because When I built my new system about 4 weeks ago, I ran several benchmarks and recorded the results. Now I ran the benchmarks again yesturday and my machine has apparently "slowed down". I suggested to my friends that some "evil software" may have slowed my system down but they disagree. The only new hardware installed on my system is a 3com Home Connect Web Cam and a Microsoft Sidewinder Game Voice unit.

Note: I ran the benchmarks after a clean boot both times.
Any other suggestions on what might be causing the slowdown?

Duron 600@800 | Asus A7V | 128MB PC100 | 32MB ATI Rage128 105/105 | Sound Blaster Live! Value | Maxtor DiamondMax Drives 15GB@7200 17GB@5400 | AOpen HQ45 Case | $12 Network Card | Ricoh 6424 CD-RW | Viewsonic PF790

 

[Soccerman]

well when you benchmark, do you USE any of these devices? if not, then they SHOULDN'T be a problem.

however as you may know, USB DOES use extra CPU cycles, somewhat like IDE (however IDE is used alot becuase it's soo much cheaper), but it shouldn't really bother much if it's not in use...

 

[obeseotron]

USB takes up CPU cycles for gamepads and cams because the basic control of the interface is done by the chipset and CPU, not the sound/capture card.