ddr3 at 1066 speeds is just wasted money. there is no real performance gain for your money until you get 1600 speeds, and even then, getting an am3 cpu, am3 mobo, and ddr3 ram, is not worth the extra money your gonna spend over an am3 cpu, am2+ mobo, and ddr2.
you will not see any real performance by choosing ddr3 over ddr2, which is basicly what you'd be basing the build around.
also, i dont wanna sound like im bashing you zune, its just that even in the original post, the OP said he was on a tight budget. if you have a bit of spare money left over, get a better gpu, or psu, or a more appealing case to you.
Hey no bother, you make a good point. I was only thinking about future processor compatability, i.e. AM3 and the inevitably faster and cheaper DDR3 to come in the future.
I only ever mentioned DDR3 because of the general use of it in AM3 motherboards. Since the price difference between DDR3 and DDR2 is not all that great now, I was suggesting to go the whole hog, get an AM3 cpu, motherboard and some cheap DDR3 memory. If he needs to upgrade the processor, he can AND if he needs to upgrade memory (i.e. when 8gb becomes the norm), he can do this easily to (DDR2 will be gone the way of DDR in 2-3years time of course)
i.e. DDR2 (Decent 800MHz)
Newegg.com - OCZ Reaper HPC Edition 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model OCZ2RPR800C44GK - Desktop Memory
DDR3 (Good 1333MHz)
Newegg.com - G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Dual Channel Kit Desktop Memory Model F3-10666CL7D-4GBPI - Desktop Memory
Total price difference, $20...
Assuming the OP not an heavy oveclocker, this will save him the need to change his mobo on top of the 'probably expensive-enough' memory and cpu. On newegg the price difference between x4 940+DDR2 and x4 955+DDR3 is $60, significantly less than a he will pay for a new mobo 2-3years from now...
@
marksct
I did not make a point of this before, remember this bit I said:
"AM3 processors support both DDR2 and DDR3. You can run an AM3 processor in an AM2+ motherboard for example..."
IF you don't want to get DDR3 and an AM3 board (i.e. to save cash as Muffin Man stated), you could buy an AM2+ motherboard. After all, all AM3 processors will work in it...and AMD will use a AM3 for at least 2 years I'd say. You will only lose out on DDR3 compatability, but as muffin man stated this is not an issue unless you get expansive, fast memory.
Hence you have 3 options:
(1) Phenom II x4 940/955 + DDR2 Memory + AM2+ motherboard (Cheapest, 940 cpu recommended)
(2) Phenom II x4 955 + DDR3 Memory + AM3 motherboard (Mid-priced, a bit of future upgradability (RAM-wise anyway)
(3) Intel Core i7 920 (D0) + DDR3 Memory + LGA-1366 motherboard (By far the fastest and Dearest)
After that you need (i) A good, reliable, branded 550W+ power supply, (ii) A decent hard drive (500gb to 1TB) and cheap DVD burner, (iii) A good graphics card (Check Sora's guide) and a cheap, high airflow case (eBuyer, in the £35 range I'd say)
Hope this helps