Need cpu upgrade advice for SFF

I'm debating a cpu upgrade and with the X2 price drops along with Conroe coming out, I need some advice.

My priority for build is SFF (small form factor), low heat/cooling/fans, then performance.
Most micro atx boards come out 2nd to the standard atx for featured boards.

My current platform is:
AMD 3200+ (2Ghz) socket 939
4x512MB DDR400 Corsair (stuck at 333Mhz due to AMD 6 rank mem controller issue)
eVGA 7900 GT video (SLI the day it drops to $150)

Options:

A) Buy an X2 3800+ (2Ghz) for $150 or an X2 4200+ (2.2Ghz) for $180
It's essentially the same chip, but the one labeled 4200 came off fabrication of a better yield. My motherboard is an Asus A8N-VM CSM micro ATX and has limited overclock.
I can change the clock from 200-240Mhz, and can adjust mem timings. I cannot adjust my memory divider. So I run my +3200 (2Ghz) at 230 x 10 = 2.3Ghz.
With the limits of my motherboard wouldn't the +4200 with the 11 multiplier be a better choice. It doesn't have the AM2 odd/even mem divider issue.

X2 3800+ could be 230Mhz x 10 = 2.3Ghz stable for $150
or
X2 4200+ could be 230Mhz x 11 = 2.5Ghz stable for $180

A couple thoughts. If there is higher demand they just label the 4200 cpus as 3800, set the multiplier and sell em cheaper (an overclockers dream), but with my limited clock adjustment it wouldn't help me as much. I know most say buy the 3800 and make it a 4200, but couldn't you buy a 4200 and make it a 4800? In my case is $30 worth an extra 200Ghz and what percentage % performance boost is that? Also I goofed and bought 4x512MB, and my RAM is underclocking. By overclocking 200-240 I can push it back up to 400Mhz. 230 seems stable right now and puts the DDR up to 385Mhz.

B) Go after the X2 3800+ 35W part for AM2 socket. My current cpu and the standard socket 939 X2 3800+ both run at 89W. For AM2, AMD is releasing new 65W parts for X2 3800, 4000, 4200, 4400, 4600, 4800. The 35W is only on the 3800. This would help reduce the heat of my cpu in an SFF (small form factor). I currently use a Silverstone SG-01 case with the NT06 passive cooler that relies on the 120mm fan in the PSU to vent heat. It works remarkable well. How much heat savings is a change from 89W to 65W to 35W? This would cost me $500 for a new AM2 motherboard, DDR2 RAM, and cpu.

C) Go after the intel Conroe. I'm not an AMD !!!!!!, and will go for whichever is cooler and faster. Conroe is a 65W part and in a review they mentioned it didn't get hotter from idle to load. (Imagine a 35W part!) This would be around the same $500 for validated conroe socket 775 motherboard in micro ATX (wont be out for a while), DDR2 mem, and cpu. Likely an E6300 or E6400. Conroe is a completely new architecture, but I have doubts that there will be a real supply at reasonable cost until Sept/Oct.

Conroe is going into an older validated socket LGA775. How long will intel sit on that socket before coming up with a new one. AMD however it seems will be on AM2 for quite some time. Higher potential of not upgrading mobo soon with the AM2.

Being SFF, and using as few undervolted fans for noise, I'm ok with performance limits.
If I end up doing a platform change (mobo, cpu, ram) I can put the old works in my wife's PC. All options seem very good. It's a good time to be upgrading cpu's.


Any advice appreciated !!

Dropping in a 4200+ 939 seems to be the simplest option, the Energy Efficient AM2 parts won't be released in the US for a month or two afaik. If you can wait, you could jump on the DDR2 bandwagon with AM2, or alternately you can wait a few weeks and nab a "low-end" Core 2 and 775 motherboard.

The price of switching over to DDR2 may not be worth it depending on your budget.