best MoBo for AMD Phenom II x4 945

why do you need to replace the motherboard? if the cpu is working dont waste your money on a new board, upgrade later when you want to do the cpu and everything. it will only draw 125w if your benching it loading up all cores anyway, for gaming and such it wont draw as much power. If you do really want to follow through with it then get something that will support an fx 8350 for future upgrade potential. As for the 6870 crossfire, dont waste your time, i had 6850 crossfire and it was problematic. Sure you get higher average fps, but your low fps often drops lower than a single card, and the stuttering is an issue, and the 1gb vram on them is a limitation, and then there are plenty of games that dont work well or at all with crossfire. Better off selling the 6870 on ebay and investing in a new card like a r9 280 or gtx 760.

it's about time to ditch that ddr2 ram, it's almost 2015 and we're up to ddr4 now. i would suggest getting some cheap ddr3. that will require upgrading the motherboard as well... because you cannot put ddr2 ram in a ddr3 slot. however, your amd phenom 945 has a memory controller that can support either ddr2 or ddr3, just depends on the motherboard it is in.

so motherboard i would suggest 970 chipset http://www.newegg.com/Product/Product.aspx?Item=N82E16813131873
here is a good review on that mobo http://www.hardwaresecrets.com/printpage/ASUS-M5A97-R20-Motherboard/1772
it has a 4+2 vrm setup so you will have no problem overclocking and overvolting that phenom cpu to extract every last bit of performance from that old betty (provided you have adequate cooling heatsink)

you can find ddr3 666.5/1333 mhz ram real cheap, maybe even used on ebay. but if you do get used ram, make sure to run a memtest right after you get it while you can still return it if it's bad. but even then, new 1333 mhz ddr3 ram is cheap.

$45 for 4 GB http://www.newegg.com/Product/Product.aspx?Item=N82E16820145322

you can start off with 4 GB of ram to get your new system going at first, and then later buy another stick to take advantage of the dual channel memory controller that phenom cpu has to offer

i got lucky not too long ago on craigslist, i bought a 4 GB stick of 1600 mhz ddr3 for $15. used of course, but as soon as i got home with it i ran a memtest and it checked out ok. was quite a steal

good luck with your build, if you only take one thing away from my post here: i highly advise you move away from ddr2 and get ddr3. because like you said that you want to slowly increase the specs, you want to get an am3+ board (so in the future you can get an fx cpu). the phenom cpu you have is an am3 socket cpu, but itll work in an am3+ socket mobo

edit: one more thing, that asus mobo i linked has an amd 850/950 southbridge chipset, which provides sata 6 Gb/s so you'll be able to take full advantage of the speeds from that ssd. as to the other person suggesting you return the ssd... nonsense. solid state storage is wonderful and i'll only ever use disk storage in a redundant raid array for archive and long term storage. always boot your OS from the fastest storage you have