Ran timings for a while and not seeing any lag: http://aikar.co/timings.php?url=6164806 Must of been deathtomb... *grumble*
You probably should just wipe your hard drive and start all over again, that's what I did on my old computer when it got these.
and i have not built any new redstone contruations in 3 weeks in fact i tore a few down so aint me people but i have been noticing the lag spikes and seen tps dip a few times
Yeah around every 5 minutes I get a 30 second spike where I can move around but the server doesn't react to my actions for 30 seconds. Also in general, aside of spikes, SMP9 has a lot more lag than other servers. Even when I'm walking around empty plots I get more lag than other servers. For example on SMP1 I'd get around 70 FPS on an empty plot where on SMP9 an empty plot gets me around 20 :\
This also happens in smp7, at some res like mine. Sometimes you have 47 or 56 fps, then you have 15 or 6 fps. Is very strange all this lag at my res.
I can handle up to 5fps, but I go insane whenever my framerate is like this. 1-2-3-LAAAAAG-1-2-3-LAAAAAG-1-2-3-LAAAAAG