So, once in a while, I see in firebug that a request takes over 15 or even 60 seconds to respond and sometimes never. Here is what I've ruled out:

• It's not the CPU, cuz every time I check the Server load its less then 6 for all 3 numbers
• It's not the memory, because thats fairly low too, less the 50%
• It's not the I/O anymore, because I've seen the graphs that Joyent sent back to me when I requested them, and they show less then 3MB of I/O (mostly all read).
• It's not the SQL performance - I've profiled every last SQL command that runs, and they're all (99.9% of them anyway) running in less then 30ms, most run in less then 5ms.
• Oh and I've been profiling all the script execution times, and even the when the problem occurs, the script always manages to finish in 50ms or less (that's 1 / 20th of a second ). Now, I do run alot of ajax calls. 1 every 2 seconds per user and I have 300 DAU+. But, even if all 300 are playing simultaneously, thats still only 150 calls per second max. The only other thing I can think of is that one of my neighbors is funky. The problem is highly intermittent. 99% of the time it works perfectly and there's excellent performance. but 99%+ is not good enough.
• Eventually the performance gets so bad I have to restart the server, at which point everything is fine again. I've done this about 4 times now. Any ideas? Note: this is on joyent, vps, intro package 256mb of ram with bursting.

here are the mysql dump info:

Traffic     ø per hour
Received    18 MiB  29 MiB
Sent    134 MiB 221 MiB
Total   151 MiB 251 MiB
Connections ø per hour  %
max. concurrent connections 5   --- ---
Failed attempts 0   0.00    0.00%
Aborted 0   0.00    0.00%
Total   9,418   15.59 k 100.00%