I have that same card in my laptop. It has 256mb of memory onboard and then takes another 256mb from your system memory to make it 512mb. My laptop runs all current games on medium to high settings and a variable res depending on the game. I would say it is the best option, either this or the nvidia 7600 series, for the 15.4' and below notebooks. Only the 17' handle the larger/faster cards! It is a good balance of heat and battery performance, so I would recommend it sense it is in a laptop. Not for a desktop though! I would also recommend another 512mb stick at some point and time so that you have use of your full 1gb of ram, and technically you would then have full use of 1.2gb of ram! That is what I did anyways.
Intel Core 2 Duo T5600 1.83ghz, 667mhz FSB, 2mb L2 Cache
1.50gb dual channel DDR2 667mhz
120gb, 5400rpm, 8mb cache, SATA hard drive
PCIe ATI Mobility X1600 256mb (512mb w/ Hypermemory)
15.4' ASUS Barebone