Change we definitely shouldn't believe in. Unless it's a change in the entire game.
Graphics maker Nvidia has announced its lower end 600 series models and (drum roll) they are indeed just re-numberings of cards you've been able to buy for some time. Rebranding to imply existing models are part of the latest and greatest generation is a move that's become depressingly common, with AMD having followed the Green Team's misleading philosophy recently. Nvidia in return seem have pushed the envelope further for such schenanigans, leaving a low-end linup that is factually speaking, a complete mess.
Entry level cards in the 600 series have been around for a while in OEM systems, with Nvidia already offering six different models (including three different GT 640s) to maufacturers such as Dell and HP. One would think that with the sheer choice available, the maker could simply pluck three models from its existing OEM lineup for retail and go from there. Nvidia obviously feels differently; none of the announced retail cards match their OEM equivalents at all. For the sake of brevity we'll stick to cards consumers can buy, but do be aware retail and OEM versions of each card are completely different. Beyond a desire to have at least numerically 'next gen' cards for every situation, it is another cryptic question as to exactly why Nvidia have let the situation get so convoluted. To stick with the theme, Atomic's thinking is that Nvidia firstly asked themselves "Can we do (and get away with) it?!!"
And as we all know from politics, apparently with good marketing yes, yes you can.
As a result the GT 630 and GT 620' are both variations on the 18-month old 'Fermi' GT 430 card, making each of them 40 nanometers of yesteryears' technology. The "GT 630" packs a fairly aenemic 96 cores at 810 MHz, with a 128-bit bus funneling 1GB of GDDR5 or GDDR3 depending on the model. This is a 110MHz boost over the GT 430 - all other specs are identical. The "GT 620" starts at an even more GT430-mirroring 700 MHz, but has a smaller 64-bit memory bus supplying its 1GB of GDDR3. The slowest of the trio is the GT 620, with a whopping 48 cores running at 810 MHz and either half or a whole gigabyte of memory talking to the cores via a 64-bit bus - a GT 520 down to the last MHz.
(The clones sadly fail to recapture the awesome of the first outing)
Another part of their thinking for this is that there is not a huge impetus for change - these cards are only suitable for very light gaming duties and as such the majority of sales are likely for HTPC and 'general-purpose' builds. Coupled with Nvidia and manufacturer TSMC's issues with the 28nm process this has left it with not quite enough reason to and not quite enough capacity for, change. Most likely AMD will not do any differently, although it has left confirming retail cards uncharacteristically much later than Nvidia has. AMD's OEM product page has shown HD 6000 and HD 5000 cards (the latter of which aren't far off 2.5 years old!) rebadged as HD 7000 cards for some time.
It is also relevant both Intel's HD 4000 and AMD's upcoming Trinity desktop parts have not only the media playback capabilities of the "new" GT 630 and 620, but are within shouting distance of its gaming potential too. This new level of rebranding in the low-end may be the first harbinger of a slow retreat of discrete from this segment. Instead of continually pushing the performance of such cards, both Nvidia and AMD graphics may eventually leave the low-end market to 'good enough' integrated GPUs and concentrate entirely on gaming cards. The one bright side for those who desire non brank-breaking gaming is that with the lack of a GT 640 or GTS 650 announcement, it seems more likely the latest 'Tesla' architecture will appear in Nvidia's midrange, as well as the GTX 660 when they finally turn up later in the year.
For now though, if you desperately want an entry-level 600 series Nvidia (or an AMD 7000 series) card, we'd suggest you just find a sticker with the desired number on it and plant it on an older card. Both manufacturers have effectively confirmed that as being legitimate.