The IdlePC Values and IOS Versions that i used to build the CCIE R/S Lab are:
[[3725]]
image = /ccie/base/c3725-adventerprisek9-mz.124-17.bin
ram = 128
disk0 = 0
disk1 = 0
mmap = True
ghostios = True
idlepc = 0x60a6d020
[[3640]]
image = /ccie/base/c3640-js-mz.124-17.bin
ram = 128
disk0 = 0
disk1 = 0
mmap = True
ghostios = True
idlepc = 0x604c37fc
For Instance 1: The 3725's were used for Routers R1 - R6.
For Instance 2: All 3640's were used for SW1 - SW4 and BB1 - BB3.
In Linux, i have noticed that 3725 performs much better as compared to 3640. On full load, means IGP, BGP, Redistribution, Multicasting and Security the CPU Load was 40%.
The Dynamips Server Configuration was:
AMD Athlon X2 64Bit 4400+
2 GB Corsair DDR2
80 Gb HDD
Fedora Core 6, 32Bit
The Dynagen Client runs on my laptop in Windows XP.