Quadro 1500 or 3450

Whe are currently running PNY Quadro FX 1500 in P4 3200, 2gig ram, Dell Work stations.
Our company just purchased us 490 Work stations w/2.66 Quad cores,2 gig ram,
w/ Quadro FX 3450 cards in them.

Should we swap in the old 1500 cards to the new systems or keepsthe 3450
in the new systems.

These cards seems to have simular levels of performance.
What do other preferr for cards?SolidworksAdministration