AMD's new HD 5670 is another sucessful product in their HD 5000 lineup. The new card delivers over 20% more performance than the last generation HD 4670, yet it consumes roughly the same amount of power. Low power consumption also means little heat which means the cooling solution can be less complex (= cheaper) and also quieter, when paired with the right fan control settings. MSI has done a good job here, the card is nearly silent in both idle and load. Just because fan noise is low, doesn't mean that temperatures need to be high. In our testing we saw temperatures well below 70°C, even with overclocking.
Overclocking potential of these new cards is quite good, MSI's card actually does better in that regard, than the first HD 5670 we tested a while back. Our sample managed overclocks well over 20% for both memory and core which translated in a real world performance increase of about 18%.
MSI has put 512 MB extra GDDR5 memory on their card for a total of 1 GB. Unfortunately this does not translate into any performance gain on resolutions below 2560x1600. While 2560x1600 is 13% faster on the 1 GB card than on the 512 MB card, it is still unplayable in all benchmarks that benefit from the extra memory. I also have doubts that future titles will change anything. Either the title will require more memory AND more graphics power, or it will run fine on weaker cards.
If you are in the market for a HD 5670, then you should save yourself 15 bucks and go for a HD 5670 with 512 MB memory, unless you are speculating on the resale value of the card. I am sure that a 1 GB card will fetch better prices on eBay than a 512 MB card, especially in a year from now. While one could criticize MSI for releasing a 1 GB card, I have to give them credit for trying something new, that other AIBs are not always willing to do.