Phenom II 720 - Northbridge confusion - Overclock.net

chris.hoops78 · 07-10-09

When you overclock the northbridge frequency in your BIOS, is this the speed of the northbridge chip on the mobo, or the IMC on the CPU die?

As I understand it, the IMC (the bit that controls traffic between the CPU and memory) *used* to be located on the northbridge, but is now moved to the CPU die in AMD64 processors.

So, when you overclock NB freq, which bit of the system are you actually changing.

Btw is the function of the mobo northbridge still to talk to the PCI-E bus and southbridge, just not the memory?

cheers

pow3rtr1p · 07-10-09

A very interesting question, actually. I would assume it's the real Motherboard NB, but you make a valid argument.

LethalRise750 · 07-10-09

Quote:

Originally Posted by chris.hoops78

When you overclock the northbridge frequency in your BIOS, is this the speed of the northbridge chip on the mobo, or the IMC on the CPU die?

As I understand it, the IMC (the bit that controls traffic between the CPU and memory) *used* to be located on the northbridge, but is now moved to the CPU die in AMD64 processors.

So, when you overclock NB freq, which bit of the system are you actually changing.

Btw is the function of the mobo northbridge still to talk to the PCI-E bus and southbridge, just not the memory?

cheers

Northbridge Frequency is on the Integrated Memory Controller for the CPU. When you overclock the NB Frequency, You are overclocking the CPU Northbridge.

The Motherboard Northbridge does indeed talk to the PCI-E and southbridge...You are also correct that it does not communicate with the memory(feature was removed to make room for the CPU NB)

chris.hoops78 · 07-10-09

Right cool. so i assume there's no option/no need to overclock the motherboard northbridge.

LethalRise750 · 07-10-09

Quote:

Originally Posted by chris.hoops78

Right cool. so i assume there's no option/no need to overclock the motherboard northbridge.

Nope, there is no need or option :P

chris.hoops78 · 07-10-09

so what on earth is HT frequency?

dansi · 07-10-09

The CPU "northbridge" = IMC, controls how the core communicate with the L3 cache, so overclocking it will gain you performance. Previous AMD cpu northbridge runs at the same frequency as core, but with Phenom, the northbridge runs lower than core. People have speculate it due to keeping the TDP down.

The current northbridge in Phenom boards are mainly the IGP...i guess.

LethalRise750 · 07-10-09

Quote:

Originally Posted by chris.hoops78

so what on earth is HT frequency?

HT Connects to the mobo Northbridge and links the hardware together if I'm not mistaken.

elito · 07-10-09

Quote:

Originally Posted by chris.hoops78

so what on earth is HT frequency?

hyper transport. and sometimes its used for the cpu clocks. - ht-fsb. its basically AMD's front side bus terminology. lol

chris.hoops78 · 07-10-09

Quote:

Originally Posted by LethalRise750

HT Connects to the mobo Northbridge and links the hardware together if I'm not mistaken.

makes sense.

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Phenom II 720 - Northbridge confusion

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