8-Core Mac Pro & CS3

Does anyone know if CS3 can actually run AND utilize all 8 cores on the new Mac Pro?

I am about to purchase the 3GHz 4-Core Mac Pro and management wants to know if its worth the $650 upgrade from the 4-core to the 8-core.

I am looking for maximum performance in Photoshop, InDesign, Illustrator, etc... The current specs are as follows:

Mac Pro Z0D8
Two 3.0GHz Dual-Core Intel Xeon
4GB RAM (4 x 1GB)
ATI Radeon X1900 XT 512MB
250GB 7200-rpm Serial ATA 3Gb/s (Boot)
500GB 7200-rpm Serial ATA 3Gb/s (Data)
Two 16x SuperDrives

So what will give me the best performance, extra RAM, more HD Space or 8-Cores?

-- Mark