Hello, all

I'm new to Bitcoin. I'm running client on Ubuntu 10.04 x86 VM with two CPUs and 2.5GB memory. The VM's running in Hyper-V on Windows Server 2008 x64, on old Dell SC1435 with Quad-Core AMD Operon 2376 and 8BG memory.
It's been up for two days, has 15 connections, and currently sees 65,564 blocks. This morning, it generated "50", and tells me that they'll mature in 9 more blocks. That seems more-or-less normal, yes?
What's odd is that it's running at 300-500 khash/s when otherwise idle, but is using only about 1% host CPU on average, with occasional bursts to 10%-20%. The bursts seem to correlate with disk and network activity, which makes sense.
Anyway, I'm curious why I'm not seeing higher khash/s, given that there's plenty of resources available.
Could it be because the VM is running without Linux integration services (which I haven't managed to install successfully)? Or could it be because I'm not port forwarding? And FWIW, I can't do that because I'm connecting through OpenVPN.
How can I increase resource utilization? Alternatively, I'm sure that Ubuntu would be happy with one CPU and 1GB memory. Would running four such VMs be workable?
Thank you. This is fun.