My experience with HD 6870 and GTX 570

This is my first time posting so please go easy on me.

Reference to the cards I used:

Diamond HD 6870:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

EVGA GTX 570:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I just wanted to point out my experience with both cards playing nothing but World of Warcraft.

My system specs:
Motherboard: MSI 890FXA-GD70
Ram: Corsair DDR 3 (4x2GB = 8GB) @ 1333mhz (due to overclock the ram mhz changed but not sure what it currently is since I am not at home)
CPU: AMD 1055T over-clocked from 2.8GHz to 3.5Ghz
CPU Cooler: Prolimatech Megahalems Rev B with Scythe Fan blowing to exhaust
Hard Drive 1 (Win7-64 ultimate and WOW): 60GB OCZ Vertex II
Hard Drive 2 (storage): Samsung T3 Spinpoint 1TB
Sound: Onboard - MSI/Realtek
PSU: Thermaltake (forgot model) 600w, modular.

My test was rather easy if not simple. I only play World of Warcraft. I am playing it with the add on string to the execute file for Directx 11 support (to be honest, not sure if it is enabled or not, I cannot really tell the difference but that is a whole other topic) I play in only 1900x1200 with all setting set to max (Ultra) and supersampling to 8x.

So I played in the same zones just at different parts of the day/night. Ran the same dungeons, with the same people. Frame rates lows for both were approx. 45fps. When I would fly around the new zones in Cataclysm, my FPS would normalize (what I normally would see with my 5770) to 60-90 fps. During Dungeons is when I started really feeling the power of both cards, my fps would burst to approx. 160 fps then drop back down to 100-120fps with the 570; however with the 6870 it would burst and hold steadily at approx. 150-180fps.

Each card got 2 days of play and the results I mentioned above remained the same if not very close to the stated fps (give or take 5fps). I did not alter the Catalyst Control Center or Nvidia Control Panel what so ever other then ensuring Vertical Sync and Triple buffering were off, otherwise they are at default settings.

I am a fan of both Nvidia and AMD/ATI however I do feel, at least in my case/situation, the 6870 performed better on my system and the cost difference was approx. $80-$100.

I will end my observation with a question for those that can give me feedback based on their experiences with WOW-Cataclysm or any other comparable game. I currently have an Asus 5770 Cucore, and I was looking to get a newer card not only for WoW, but looking into other games like Dragon Age, Rift Online (when that becomes available), FF14 (I can only run that in a very small resolution to maintain good quality graphics and high FPS), and pretty much any other big MMORPG that will come out in the near future. I was considering a second 5770 but most threads suggest that you stick to a single card solution before moving into multiple cards. My board is capable of CFX and if that would offer me better FPS at 1900x1200 with a second 5770 I do not want to rule it out. But if dishing out $100-$140 for a second 5770 really worth it? OR am I better off with a 6850/6870, 570?, maybe even 6950 if price is nice? Be mindful I am looking for best bang for buck, so lets base it off that and thanks in advanced for the help.

Happy Holidays! See ya in 2011!