Well, my Entry 3DMark Vantage with the HD 3000 on an i5-2310 was E6121
A GT 220 would probably get E8600+ and a new low end GT 520 about E10000.
So, as you can see, it's better than past motherboard graphics but still not as good as even the low end of more recent cards. The HD 5450/6450 in particular is a good half height card with low power requirements (20W max) to replace onboard graphics.
However, I don't game on my mini and I do just fine with the onboard HD3000 on an i5-2305S running a dell 30" monitor @ 2560x1600 resolution for streaming video, blu-ray, etc.
Ok so for the HD 3000 most entry level cards will replace them. But I was wondering about the original Intel HD that came in 2010. Since my laptop is the original Intel HD and I was wondering what kind of card will it perform like if it was a Nvidia or ATI type card. I assume it's like the GeForce 9400 or maybe ATI Radeon HD 4500 or something like that. But maybe my IGP is close to the Inte HD 3000 series so it's like the ATI Radeon HD 5450. I don't know though. I never compaired my Intel HD to newer GeForce cards. My moms old desktop has a GeForce 7300 GT and it has 512mb DDR2 ram. My Intel HD on my Sony laptop is alot better than that that's forsure. Anyways if anyone knows what kind of Nvidia card or ATI card performs like the original Intel HD I would appreciate it.