I was looking at the AMD AM2 4000 x2 and 4200 x2
For gaming and such, which do you think is the better choice?

4000x2
2.0GHZ
1Mb x2 L2 cache

OR

4200x2
2.2Ghz
512kb x2 L2 cache

They'd be similar in games... the 4200+ would be alot cheaper now though, as 4000's are no longer in production.

4000 = $399
http://www.newegg.com/Product/Produc...82E16819103739
4200 = $183
http://www.newegg.com/Product/Produc...82E16819103747

I recall reading somewhere that more clock speed makes for a much larger improvement than more L2 cache when it comes to games. Of course if money is an issue you can overclock a cheaper x2 to a much higher clock.
Personally I went with the 3800+ x2 due to money restraints, and have it clocked up to 2.7ghz stable with only the addition of a TT Big Typhoon. Even if you don't feel comfortable putting a bigger fan on and messing with multi/HT/DDR timings, I was able to simply bump the clock to 2.35 without changing a single other setting. (had two different brands of PC3200 512mb sticks in it, didn't do anything but switch them to 1t) That ran stable as the day I bought it with stock cooling.
Of course I have never played with anything that has a 1mb L2, so I'm probably not the most qualified on the comparison bit, I can only tell you what I've done. (my 3800+ @ 2.7 is benching comprable to one of the FX chips in Sandra lite, but I'm at work and not at my computer, so I can't tell you which right now, I'll edit when I get home) In conclusion, I think it would be wiser to save the money on the cpu, overclock it, and spend the extra cash on a nicer video card, that route has worked very well for me.

Well, i recently red something about this...i cant remember where...i think it was in Max. PC. They're going to be nearly identical in gaming. The 1mb cache makes up for a lower clock speed, while in the other the higher clock speed makes up for the 512 cache. So, there shouldn't be too big of a difference.

Well ,Ive found that for folding@home the bigger cash is more important .
But I think for everyday use theres little difference.