The Guru of 3D posted a review on the PowerColor Radeon HD 4850 with 2 GB memory

The graphics card we will test today is based on the immensely popular Radeon HD 4850. Probably the best value card one can buy. These cards at default come with 512 MB gDDR3 memory.

Now, I can see a manufacturer double up that memory to 1 GB. The effect would be small but measurable when you would like to game in very high resolutions. Then there is an incremental step to that as well. And that's what we'll test today. PowerColor released a Radeon HD 4850 graphics card with, get this ... 2 GB memory. That certainly brings a smile to my face, as if anything, I like innovation.

But even yours truly is going .. "Hmmm, that's not gonna work, is it?". You can read the review right here

Radeon HD 4850 with 2 GB tested