Experience with 8400m GS to core i5-520 Intel HD

I know this is the gaming forum but this is the only place that I think I can trust an answer.

I don't play games whatsoever on my laptop, currently have a 8400m GS. This card is OK. It's not even very good for HD playback in my opinion but it does a decent job. I have seen benchmarks but I don't feel like they can tell the story like a person with experience can....

If I go to a laptop with intel hd graphics and i5-520 processor, how much better are things going to be from day to day? I connect to an external 1080p monitor at home all the time via HDMI and the gfx gets slightly more laggy when I do but it's not unbearable.

Opinions are appreciated. In case you are wondering, I need a thin and light laptop (3-3.5 lbs), at a reasonable price, with a good docking station. It seems as though the R700 is going to be perfect for me (vaio z is wayyy to overpriced) but frankly it would be ideal if they would have just thrown out the optical drive and put in an external graphics card with switching capabilities. Grrr.

I'm also thinking about maybe getting an external graphics card for home use (the MSI one seems cool) but I don't think that bad boy is plug and play, which would be pretty annoying for my purposes .

EDIT: I have a T8300 CPU

 

I wonder what your current CPU is, that might make more of a difference.

The 8400m has a known fault, it may die.
Also the intel GPU will make your notebook cooler and have a better battery life.

With external graphics, I hope you have seen this:
http://forum.notebookreview.com/gaming-software-graphics-cards/418851-diy-vidock-experiences.html

I had an nvs 130m which had the same G86 core as the 8400m, not a great gpu.
But I dont have the latest intel graphics to compare it with.

 

My 8400m died recently...just had it warranty replaced. I edited my post with my CPU (T8300) and yes I agree with you about battery life, but what I'm really worried about is not getting a GPU that is at least better than what I'm using right now. I feel like I shouldn't be seeing lag if I'm not doing anything that's 3D, but I am right now...wondering if intel HD has problems with intense 2D / HD content?

 

Last I heard, the Intel i5 matched the 9400M.

 

The mobile ones have lower graphics core clocks which limits performance.

 

You are correct, I appreciate that.

I have researched all the figures (memory, shaders, etc) and benchmarks but I am looking for someone with real life experience using 8400m gs and intel hd on a core i5/i7 mobile processor.

Thanks!