It really is much better than the 5670, though.
http://www.hwcompare.com/106/radeon-hd-5670-vs-radeon-hd-5850/Also, the reason you see some PCs that will go 6GB and some will go 8GB is depending on the chipset and whether it is dual channel or triple channel. Dual channel benefits by having sets of two where triple benefits with sets of 3.
