Yes, imho move up to the 5750. It has twice the SP's as the 5670. If you can get it cheap, then its 'ok' . But I see them priced at over 100 dollars at times. It fills a niche for not needing external power.
The 5750 has 720 SP's, the 5670 has 400SP's, if you want double the SP's then you want the 5770.
The 5670 will play most games quite good at lower resolutions, basically 1440x900 and below and it will play most games on high (even Crysis, I can do that with a 5650). At high resolutions something like a 5750 would be a good step up.
We were impressed with the performance of the ATI Radeon HD 5670 compared to the GeForce GT 240. In the sub-$100 segment, the ATI Radeon HD 5670 currently provides the best gameplay experience, period. It is still yet to be seen if it has what it takes to push DX11 effects in games, such as Tessellation however.
If you are on a budget, and demand the best performance for the money, the ATI Radeon HD 5670 is your best choice. If however, you can spring $30 more dollars, you will find that the Radeon HD 5750 leaps ahead of the Radeon HD 5670 quite a bit and offers a much better gameplay experience. Unless you just simply can’t spend over $90 no matter what, we would stay away from the GeForce GT 240 for gaming, throw in another $10 and you’ll be happy you did.
The pricing in that quote is a bit off these days though. On newegg right now the cheapest HD5670 of a good brand is a full $52 less than the cheapest HD5750 of a good brand(before rebates.)
With current pricing on the HD5750 I'd just forgo DX11 and get an HD4850 or GTS 250 at this point probably if I wanted something a bit more powerful than the HD5670.
I actually quite like the 5670, I've run a couple of them and built some computers using them and they perform quite well for a budget card. My friend has recently ditched his 8800GT and gone to a 5670, and on most games, he's getting a better frame rate with AA turned on; the only thing that's taken a blow so far is PhysX related stuff, but that's understandable.
You didn't need an uber PC to play Crysis, my old 7300GT could play it at 800x600 playably.
Depends on the setting and resolution. Most hardcore enthusiast gamers wants at least 1920 x 1200 and maximum graphics settings.
I played it on my old X1900XT @ 1920 x 1200 with medium quality settings. Unfortunately, that card died in Sept. 2009. The good news is I bought my HD 5850 before it skyrocketed into the $300 range. Never bothered to replay Crysis yet though with my "new" card... maybe next year, maybe not...