Final Cut Pro + Mac Pro = Problems??

I am about to buy a MacPro and I am upgrading from a:

Imac 2.66ghz, Intel Core Duo, 4gbRAM and a ATI Radeon HD 2600 Pro

Now here is what I am upgrading too:

Mac Pro 2.26GHz 8-Core Intel Xeon
Two 2.26GHz Quad-Core Intel Xeon "Nehalem" processors
6GB (6x1GB) of 1066MHz DDR3 ECC memory
640GB Serial ATA 3Gb/s 7200 rpm
18x SuperDrive (DVD±R DL/DVD±RW/CD-RW)
NVIDIA GeForce GT 120 with 512MB GDDR3 memory

So after investigating I have read that FINAL CUT PRO can not use more than 4gb of ram and that people who have upgraded to a more powerful setup like that of above are being dissapointed because rendering times are not that much faster because of FCP issue of not being able to optimize the power of your mac pro

Someone said wait for Snow Leopard... okay why? Final Cut Studio 3 is not coming any time soon? What will Snow Leopard do for me? FCP is still going to be capped at 4gb of ram

The reason I am upset is because I need to upgrade computers pronto.. and the buying process and finding someone to talk to about this is such a pain in the butt. None of the genious' in the mac stores have any idea about FCP not being able to optimize an 8core Mac Pro with all its power.

And you know what about those using Premiere? You can buy a computer that is SUPPPER Fast for less than the MAC PRO and I am wondering where the RAM is capped in that situation? Anyway its not just about the RAM it is about me being able to Render something that was chroma keyed a lot faster.

I am using 108080i from the XH-A1.

I love Apple and I like many other editors are pissed. thanks for reading :D

(btw I am sure i could always make things faster by capture my footage and convert to 720 but I dont want to do that.)