Preface: I'm Green...I just recently plugged in some Alesis M1's into my Mackie 1620i and they sound awesome in comparison to the ultra cheap computer speakers I was using previously. Maybe the low quality of the comp speakers didn't allow me to hear them clear enough, but it seems that since I have installed the M1's the pops and clicks during mixing are relatively frequent....Maybe every 10-20 seconds. With all the various fx being employed my CPU is somewhere just below 30%. I wouldn't think 30% would be overly high, so why the clicks and pops?...tips appreciated.

One thing to check is if the clicks are part of the file, or part of the playback. Look very closely at the wave forms and see if the clicks are drawn in the wave forms. If the clicks are visible, then it is NOT a problem with your CPU, but rather an issue in your input chain (Room, mic, cable, pre, a/d). If the clicks are not visible then the problem is in your playback chain (Hard drive, cpu, D/A, cable, speakers). If it's visible, Zoom in on it, and post a screen shot here. If it is not visible, Look at the counter in Reaper (the black box with the clock in it). If it is flashing red then you are overloading the CPU. If it is not, check the performance monitors in task manager and see if you're overloading anything. Also, loop a section and see if it clicks in the same spot each time, or at randome. [Edit] Sorry to post a lot of the same info as drybij, we appear to have posted at the same time.

Thanks for the replies guys. Looks like I have a bunch of ideas to look into and I appreciate you guys sharing your experience and knowledge. I have been thoroughly impressed with REAPER and how easy it is to jump right in and learn. I've been using it for about a month and I've read through the entire User Guide over the past few weeks. Its been a lot of learning but it has happened remarkably fast. I have definitely narrowed it down to playback so at least I'm not recording pops, and the PC is pretty much bare. With that said, there are some excellent points in the above posts that I will certainly be looking into. Just to name a few- everything is on the boot drive, there is a virus scanner running, I'm using a firewire connection and have no idea what the chipset is. Its really great to have these responses in writing because I didn't set up the PC in question and I know very little about computer hardware other than knowing what is desirable in a hot-rod PC. So I'll be passing on some of these comments to see what our next move will be. Thanks a ton, really.