do SPP and MCP (northbridge and southbridge) multipliers have an effect on overclocking?

[Frugal1ty]

in my BIOS (foxconn C51) there are multipliers listed as follows
nForce SPP --> nForce MCP
nForce SPP <-- nForce MCP

i lowered them from 5x to 4x and seemed to gain some stability at HTT above 300. does that make sense? also, are these multipliers similar to HT multiplier where overclocking it gives you no performance advantage?

 

[Sylvanas]

The max multiplier for X2 CPUs is 5x. What that means is 5x your HTT= HT Frequency. It's generally considered that it's best to keep this at around 1000mhz, if you go over you risk instability as you pointed out. It does impact performance somewhat but not to the extent other latencys/frequencys do. Phenom CPU's allow for the HT3.0 spec whereby the max multiplier is I think 13 for a total frequency of 2600mhz. The two settings you describe in the BIOS I would assume would be upsteam/downstream and they should generally be left at the same multiplier.

 

[Frugal1ty]

Originally posted by: Sylvanas
The two settings you describe in the BIOS I would assume would be upsteam/downstream and they should generally be left at the same multiplier.

by 'left at the same multiplier you mean: matching the HT multiplier, or left at the default of 5x?

 

[Mondoman]

Neither, he means both settings should be set to the same value.

 

[myocardia]

Originally posted by: Mondoman
Neither, he means both settings should be set to the same value.

Right, which in this case should be 3x.

 

[Frugal1ty]

Originally posted by: myocardia

Originally posted by: Mondoman
Neither, he means both settings should be set to the same value.

Right, which in this case should be 3x.

3x? default is five.

 

[Sylvanas]

Yes, but in order to maintain the 'stable range' of near enough 1000mhz (3x300ht= 900mhz HT Frequency) it's recommended to keep the multiplier at 3. At 5 you'd be at 300x5=1500mhz and thus quite unstable in most scenarios.