No, the model lines have been bumped up.
The 7750 replaces the 6600s.
The 7770 replaces the 6700s.
The 7800s replace the 6900s.
And the 7900s are a new higher tier range.
It's very well explained by Anandtech and it shows how people are getting ripped off. The model names are irrelevant - all that matters are the prices and performance.
The HD6670 GDDR5 launched at between £75 to £100 which was in the same range as the HD5750/HD6750 cards. There was a premium on the card as it was bus powered unlike the HD5750/HD6750. The HD7750 is around the same price at launch(£80 to £110) and has basically combined the function of both cards now. You do realise that the HD6850 1GB at launch was between £134 to £160? I tried getting hold of the £134 model(launch day special from some retailers),but most HD6850 1GB cards were £145 to £160
IIRC. I have an interest in slot powered and low powered gaming graphics cards as I am an SFF fan myself. At that point the HD5770/HD6770 were still around the £90 to £100 mark(some models cost more). The HD6870 1GB ranged from £176 to £205 at launch.
At that point HD5850 1GB and HD5870 1GB cards had also dropped in price too, which made the value context of the HD6850 1GB and HD6870 1GB also open to debate by many people at the time.
The HD7770 pricing is from around £110 to £145,with most under £130. The more expensive models are pre-overclocked ones. If anything pricing seems similar to the old HD5770 1GB at launch(whether the HD7770 is worth it though unlike the HD5770 1GB is another question especially with the HD6850 1GB and GTX460 1GB ATM).
The HD7850 will replace the HD6850 1GB and probably will be in line with the £150 to £200 range,depending on the cooler and the level of factory overclock and amount of VRAM. It also has only one PCI-E power connector which does indicates it is an HD6850 1GB replacement too.
I suspect it will be the HD7870 which will be placed higher but probably more in with HD6950 2GB pricing,but replaces the HD6870 at the lower end of its pricing and the HD6950 2GB at the upper end. There will probably be 1GB models which are more HD6870 1GB replacements and 2GB models which are more targetted towards the HD6950 2GB.
The HD6950 2GB varied from just above £200 at launch to nearly £270 for pre-overclocked models with a non-reference cooler. The lower end HD6950 2GB pricing was not too far off higher HD6870 1GB pricing. Most HD6950 2GB cards were around £220 to £230 IIRC.
OTH,the noise was that the HD6900 series were meant to be priced higher,but the GTX500 launch meant AMD had to price them lower.
I suspect that there will be another intermediate model to bridge the HD7870 and HD7950.
The thing is AMD is reducing the number of
new GPU lines(not card lines) it has released with the HD7000 series,and hence each line has to cover more price points(until Nvidia gets around to releasing their new GPUs). On top of this AMD card launches seem to be following the lead of Nvidia,ie,have not only cheaper referance cards but more pre-overclocked and more expensive custom cards at launch.
AMD had three card lines with the HD2000 series - 24XX,26XX and 29XX(3 new).
AMD had three card lines with the HD3000 series - HD34XX/HD35XX,HD36XX and HD38XX(3 new)
AMD had four card lines with the HD4000 series - HD43XX/HD45XX,HD46XX,HD47XX and HD48XX(4 new)
AMD had four card lines with the HD5000 series - HD54XX/HD55XX,HD56XX,HD57XX and HD58XXX(4 new)
AMD had five card lines with the HD6000 series - HD64XX,HD65XX/HD66XX,HD67XX(rebrand),HD68XX and HD69XX(4 new and one rebrand)
AMD has five card lines with the HD7000 series - HD73XX/HD74XX(rebrand),HD75XX/HD76XX(rebrand),HD77XX,HD78XX and HD79XX(3 new and two rebrand)