It has seemed slow for some time (certainly the 1.18.5 RCs), but the RCs seem to have *terrible* login screen performance - dropping as soon as the background graphic loads. Keystrokes take an appreciable fraction of a second to echo and often misses backstroke keystrokes. The performance of the viewer itself seems ok once it gets going, so I'm not quite sure what to make of this.
FWIW:
Second Life 1.18.6 (0) Dec 4 2007 18:07:11 (Second Life Release Candidate)
CPU: Intel(R) Core(TM)2 Quad CPU @ 2.66GHz
Memory: 3903 MB
OS Version: Linux 2.6.22-14-rt #1 SMP PREEMPT RT Sun Oct 14 22:53:32 GMT 2007 x86_64
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: GeForce 8600 GTS/PCI/SSE2
OpenGL Version: 2.1.1 NVIDIA 100.14.19
LLMozLib Version: 1.1.0 (Mozilla GRE:1.8.0.12_0000000000)
Viewer Digest: 4a1ac10c-6822-fd60-9e3c-5243a242c047