AM3/AM2/Athlon 64 and .... socket

[ManT]

Just wonder how come a motherboard's socket can fit those AMD CPUs:
AM2+, Athlonn 64x2, Athlon 64 and Sempron?

Do they same pins?

 

[buzznut]

Yes, 940 pins.
Ok so it seems AM2 and Am2+ use 941 pins, and AM3 uses 938. However AM3 is backwards compatible with AM2 with a bios update, so apparently the pin layouts are very similar.

 

[ManT]

I have a socket 939 Athlon 64 3200+ cpu, can I use this cpu on AM3 motherboard?

 

[mindless728]

nope, S939 is too old and can only fit in the appropriate socket (aka S939)

 

[ManT]

"However AM3 is backwards compatible with AM2 with a bios update"

What exactly is this mean?

If I put a AM3 CPU eg. Athlon x2 245 onto a AM2+ motherboard, does it boot into BIOS?

If no, how do I update the BIOS?

 

[ManT]

Sorry, I should make myself clearer:

To build a new system and install WinXP:
1) Put the AM3 cpu onto my AM2+ motherboard
2) Boot from DVD drive
3) Start XP setup

Can I do a normal Win XP installation up to here?
If yes, then after Win XP installation, should I boot into BIOS and do an update?
This add another question, as during XP setup it may need to reboot the pc couple of times, will there any problem as AM2+ motherboard may not recognise AM3 cpu.

Or should I update the BIOS before Win XP installation?