How good is the 9800GT?

It will be a vastly faster than your 6600gt. You will have very little problems except for maybe heat but that is normal but avoid the low power version since they are very problematic. Try to find a 55nm version with 6pin power connector since they run cooler and overclock better.

Thanks - This is actually the exact one I am getting.

http://www.tigerdirect.com/applications/SearchTools/ite...

I just realized it was a GTX. Silly me.

That is high for a single GTX+ but try to find one that is cheaper but even the 9800gt does very well. Good luck and enjoy the new card.  

Me? I'm thinking you could find an ATI 4870 in that same price range... and that would clearly be a faster card. With free shipping, you should be able to find a 4870 for around $150.

http://forums.techpowerup.com/showthread.php?t=62698

If that graph is correct, that's 40% across the board increases in FPS.

I am not very familiar with Radeon though, as I have only have nvidia cards, and I trust them the most. So I will be sticking with them for now. Thanks, though.

Brand loyalty will never help you... only hurt. Try to think about that with as open of a mind as possible.

I've owned multiple ATI and Nvidia GPUs. Currently I have an Nvidia 8800 GTS in my laptop and an ATI 5850 in my desktop... both are great. I think that Nvidia still has an edge in the mobile GPU market... but desktops? ATI owns that segment. That explains my purchases... I guess that makes me a switch hitter. Value trumps brand loyalty in my book.

To each his own!

A 9800GTX+ is roughly comparable to a GTS 250 except it will use more heat and power I believe. NewEgg has 512MB versions of the GTS 250 for as low as $109 if I remember correctly; that's your best bet.

What are the rest of your system specs, The Cloak?
I ask because the 6600 is an old card, and I'm not sure if your system has the CPU power to drive a 9800GTX, or, indeed if the motherboard has a PCI-E slot. Also bear in mind the 9800 needs more power than a 6600GT, does your PSU have the connectors and output on the +12v rail/s to power it?

^+1
You should pay attention whether rest of your system is compatible or not...

Good point by coozie. I was gonna ask the question myself but he beat me to it. Can your current PSU handle the power requirements of a modern videocard?

if your power supply does not support the 9800GT
then buy the GT240 or I prefer the new series of
ATI 5750 / 5770 with support diectx 11  

I've actually just decided on an entire new motherboard, processor, video card and RAM.

I will now have a:

nvidia 9600 GSO 768MB
Biostar TA790GX 128M Motherboard
AMD Phenom X4 9750 Quad Core Processor
Corsair 2G DDR2 Dual
600W PSU

Ordered the parts the other day, just ignore this thread now.