Capture CIS and PSpice simulation problem (SPD)

Currently, I'm doing a simulation of circuit--Actually, it is not a
circuit, a Power LED modelling--that has almost 38,000 of nodes. As you
can imagine, the circuit has intense and extremely complicated.

I'm using Capture CIS to edit and sketch schemetic of circuit, but this
is one problem. Although my PC is not ancient(?) silicon dough, (P4
2.8C, 1.5G DDR, ATI X700) the Capture CIS program runs very
slow--almost stuck--when opening, editing the Massive Diode modelling
circuit. Of corse, working with simple(about 100 nodes?) circuitry does
not cause speed down or lagging. It should be ridiculous to complain
about this problem with tens of thousand noded circuit, but it have
strange situation. If we open the same Massive circuit in OrCad 9.X
version's Capture Package, it runs as fast as usual. However, when
opened with Capture integrated with OrCad 10.X, Whoops, even making
only one scratch on that circuit takes almost 5 minutes.

Secondly, when performing simulation the Massive LED modelling circuit
with PSpice A/D, it takes more than 1 hour to finish simulation run.
The sweep step was 26. But, even the sweep reduced to only one sweep,
it takes almost 30~40 minutes. Strangly, with HT(P4 2.8C has Hyper
Threading), the simulation process does not eat up more than 50% of CPU
usage. I wish to reduce simulation time, even the Simulation process
takes whole CPU usage. Or, if the PSpice runs single threaded in
default, I want to change its setting to use multi-threaded simulation
environment.

Can you provide any advise with my problems?