How much fps will GeForce5600 Graphics give u?

how much fps will tht graphics card give u and how much will this comp give me:
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Windows 7 Home Premium - English/French
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AMD Athlon™ 64 Processor TF20 (512 KB L2 cache, 1.60 GHz)
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15.6" HD 1366 x 768 pixel resolution
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2GB DDR2 SDRAM
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250GB hard drive, integrated Super-Multi drive, 5-in-1 card reader
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ATI Radeon™ HD 3200 Graphics
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802.11b/g WLAN, 10/100 LAN
will this comp give me like 50fps or more? so is the ati hd 3200 graphics card better than geforce 5600 or worse?
Last question: does graphics card memory matter more than the graphics card class/number?