poclbm causes 100% usage of both my cores on my AMD Athlon 64 X2 Dual Core 6400+.
poclbm sees my GPU as

• GeForce 8800 GTX

Ubuntu 10.10 x64
GeForce 8800 GTX (128 CUDA cores,768 MB Memory, 384-bit Memory Interface) on PCIExpress x16
NVIDIA Driver Version: 270.41.19