My first thought was that they ripped you off, because the 5700LE is a stripped down version of the 5700, and comes with core/memory clock speeds of 250/400mhz, while the 5600 PCI has core/memory clock speeds of 325/550mhz.  But clock speeds don't always count for everything.  Take into account the Radeon 9600xt and 9700Pro.  The 9600xt has much higher clock speeds than the 9700Pro, but the 9700 will beat the 9600xt in almost every instance.

The 5700LE has much lower clock speeds than the 5600, but it also carries the architectural improvements that the 5700 enjoys over the 5600.  Here are a few pages of a review that included the AGP versions of the 5700LE and 5600.  If you notice, even though the 5700LE is clocked much lower than the 5600, in most cases their performance is almost identical.  Here ya go:

http://www.digit-life.com/articles2/digest3d/0704/itogi-video-cod-wxp.html

http://www.digit-life.com/articles2/digest3d/0704/itogi-video-u2-wxp.html

http://www.digit-life.com/articles2/digest3d/0704/itogi-video-fc-wxp.html - in this game, the 5700LE handily beats the 5600

http://www.digit-life.com/articles2/digest3d/0704/itogi-video-traod-wxp.html - here, the 5700LE gets almost double the framerate of the 5600, even though both are unplayable at the framerates shown

From my experience with PCI cards, they tend to follow the same trends that their AGP counterparts do.  In this case, I would definitely keep the 5700LE, and thank Amamax for sending you a better PCI card than the 5600 you originally ordered.

http://www.ivmm.com/inno3d/geforcefx/products_gf_fx_5700le.html

And

http://www.ivmm.com/inno3d/geforcefx/products_gf_fx_5600_reviews.html

For the tech specs on each card.

Are you using that in a 2400 Dell system? If so, that 5700LE is great news, another PCI videocard that is compatible!

hi, yes , im using it in a dell 2400 2.66ghz 512mb, 80gb hard-- so as far as fps are concerned, should i keep the 5700 over the 5600.   or maybe i could overclock it .  but im a little afraid of messing  up the computer unless its not that hard to do. could someone advise me on how to do this

Keep the 5700.

hi, thankyou very much for that information.

doesn't the 5700 LE PCI card have a 64-bit memory interface?  you didn't find the card too slow?