Graphics card ATI 5450 DDR3 -vs- 5550 DDR2 both 1GB

pcotu

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Jun 15, 2011
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i bought a computer. It said it came with an ATI HD 5450, but it didn't.
Take it back to the store & they offer to install an 5550 cause they don't have a 5450.
I know that the computer says it has a DDR3 RAM & the graphics card was supposed to be (the 5450) a DDR3 bus.
The 5550 graphics card is a DDR2.
Will the 5550 DDR2 graphics card be compatible with the RAM DDR3?
Will it cause problems?
Is the 5550 DDR2 slower than the 5450 DDR3?
any other things I should know / consider?

here's a page with specs on the computer:
http://www.bestbuy.com/site/Asus+-+Essentio+Desktop+/+AMD+Phenom%26%23153%3B+II+X6+Processor+/+8GB+Memory+/+1TB+Hard+Drive/2634102.p?id=1218341075428&skuId=2634102&st=asus%201730&cp=1&lp=1