I have 120 (9500 GT) and just purchased 610.

Did I downgrade?

I know it might sound like I'm asking a stupid question but apparently the series number doesn't matter much from what I've read?

Also if I have downgraded, can I at least cross fire these two cards?

The 610 is an upgrade.

http://www.geforce.com/hardware/desktop-gpus/geforce-gt-120/specifications

vs.

http://www.geforce.com/hardware/desktop-gpus/geforce-gt-610/specifications


But no, I'm pretty sure you can't SLI the cards.

according to passmark benchmarking tests it could be a slight downgrade
389 to 350
http://www.videocardbenchmark.net/gpu_list.php

Thanks...I'm noticing memory interfface to be larger on my old card but the 610 to have more CUDA cores....how much of a leap up would you say that 610 is?

Here's you two cards benchmarked and rated:

9500 gt Passmark G3D Mark (higher is better): 290 Rank (lower is better): 600 [url=]http://www.videocardbenchmark.net/gpu_list.php[/url]

GT 610 Passmark G3D Mark (higher is better): 350 Rank (lower is better): 493
[url=]http://www.videocardbenchmark.net/gpu_list.php[/url]

Here's what I came to find about nVidia cards

The first number is the model number

So a 120 is model number one.

Usually about 7 to 9 different models are presented throughout the year.

But a higher model number does not necessarily mean better...it just means the actual
architecture of the card is a little different

For instance model number 2 (2 Series) might not have a fan where as model number 6 (6 Series) has one.

The strength of the card is measured by the second number.

So a 120 is one step better than a 610

Fortunately I was able to pull the order before it shipped and got an ATI HD 6 series card instead which cost me about fifty bucks more.
Oh

An ATI chokes on strong PhysX features.

For instance I can only turn PhysX on to low level in Arkham Asylum, any further and I wind up with frame rates below 20.

If I leave it off completely I don't get any particle affects like mist.

With nVidia (for which PhysX is tailored) you can leave Batman's PhsyX off and still get the mist but it doesn't look as real as Readon with PhysX set to low.

So in instances of PhysX games, I suspect top line nVidia cards will handle those better than topline Radeon cards.