Which video card should I buy, a 1GB GDDR4 video card or a 512MB GDDR5 video card?

I am currently building my own computer and am looking at video cards to buy for it. I have looked at a few and and not sure what the difference is between these two video cards. Could someone please point out which one they think would be better to get?



So what better in your opinion? A 1GB GDDR4 or a 512MB GDDR5 video card?



Here are the two video cards that I can not decide on:



512MB GDDR5: http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=250290183434



1GB GDDR4:http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=250290240698



Thanks for all the help|||the 4870 will destroy the 3870 x2. The memory doesn't have to do much with the performance. It's the specifications that matter. I remember my friend had a 1 GB of GPU memory and I had 128MB and his GPU couldn't even run Counter-Strike Source but mine ran is perfectly. So don't worry about the amount of RAM the GPU's have. GDDR5 is also better than GDDR4. Definitely go with the 4870. |||hmm, i'd say it's pretty even. because 1gb of gddr 4 = 512mb in GDDR5 so i think there prettymuch even i would go with the 1GB of GDDR4. but either way there both great card's!|||I would buy the 1GB of GDDR4|||def the 4870