RAM compatibility

[Nemesis565]

Sorry if this is a n00b-ish question, but I couldnt find any info anywhere..

I'm planning on upgrading my CPU and mobo, my CPU is slow and the mobo is beginning to fail.

Ive seen a nice mobo (DFI Lanparty UT RDX200CF-DR) (socket 939) on Ebay and an AMD 4800+ (also socket 939).

The question is, will my RAM be compatible? The mobo supports "PC2100 (DDR266), PC2700 (DDR333) and PC3200 (DDR400) DDR SDRAM DIMM" modules, according to the seller.

I currently have 2* 512mb DDR PC3200 modules, CPUz says they are running at 166mhz with a CAS latency of 2.5

Will these work on the mobo? They should since they are PC3200, but I'm not sure... My current CPU is an AMD 3200+ if that's any help

I cant post any screenshots becuase this is my first post, so heres the info:

Memory page:
General:
Type: DDR-SDRAM
Size: 1024 Mbytes
Channels: Dual

Timings:
Frequency: 166.6mhz
FSBRAM: CPU/12
CAS Latency: 2.5
I dont think the rest is important.

SPD Page:
Module Size: 512MBytes
Max Bandwidth: PC3200 (200mhz)

The timings table is 166mhz for the 2.5 Latency column, and 200mhz for the 3 Latency column.

The modules are both identical and are Elixir branded (thats what it said when i google'd the serial number atleast), they are currently in dual channel mode.

Now, there is another issue aswell.
Ive had my eyes on a Corsair XMS DDR400 module (1gb) for a while now. It's also PC3200 and CAS Latency of 3 according to the seller.

The mobo Im planning on getting has 4 slots and a max of 4gb RAM.

Would the XMS module work with the 2 others (if they work at all that is)? Will it have to slow itself down at all or run at full speed?
Also, would i be able to run the 2 Elixir modules in dual channel with the XMS in another slot, or whould that stop dual channel working/slow it down.

Thats about it, sorry for the long post. This is my first time upgrading anything apart from the GPU and I want to make sure it all goes well.

[killie99]

If you set the ram timings to auto then all the ram will run at the speed of the slowest module. If you manually set the timings at go above the default settings of the slowest module then you are overclocking and how successful you'll be will depend on the individual memory modules that you have.
As a rule of thumb, fit memory in matched pairs as anything other than this is likely to slow the system down.

[kalniel]

Right. It looks like at the moment you don't have very good ram, so to run it at 2.5 it's had to slow down from 200mhz to 166. This isn't very good and will be slowing down your system.

The good news is setting it to cas3 should allow you to run at 200mhz.

Adding more cas3 200mhz ram (PC3200) should allow you to run the whole lot at 200mhz, cas3, so sounds like a good move.

Going to 4 banks might mean that you can't run 1T timing, but don't worry about that in the slightest.