--Question about FSB, chip speed, and memory dividers--

[Battlewaffle]

Hi,

I'm putting a new A64 system together this week. Just had a couple questions. I appreciate the help if you're able to provide any information.

I've got a 3800+ Rev E (Venice) core that I'm gonna be OC'ing to 2.8ghz. Now it's multi-locked at 12x, so I'm gonna run my FSB and memory speed at 234mhz true. (DDR468)
The memory I'm using does this speed easily while still at 2-2-2-8. It's a gig of the new OCZ VX gold pc4000 running at 3.5v on a DFI lanparty nF4 Ultra-D.

My question is about people using memory dividers, like in my case, I would be able to use a divider to run the memory near 234mhz still (in order to get 2.8ghz on chip), but be able to run the FSB higher than 234mhz true? Does that not affect the core clock on the chip? or is that locked at 200mhz independent of the FSB? There must be some limitation of running the FSB too high, and that's another thing I'm asking. Does the FSB speed affect the PCI-e clock, PCI clock, or CPU core clock?

If anyone has a link to a post that talks all about the affects of OC'ing and what it does to the buses in a modern A64 system, please link it. Or if you just know all about it, then please explain 🙂

 

[MustISO]

The FSB or HTT (for AMD) affects the memory and the CPU clock. It also affects the PCI and AGP buses but any good mobo will have locks for PCI and AGP. You only have to use memory dividers if the memory can't run at the FSB/HTT. If you memory can run at 234, then don't use any divider.

 

[Battlewaffle]

Gotcha, now running 234mhz on the memory with a 1:1 divider for FSB is what I'm looking to do then, will the CPU core run fine at 234mhz still? And does this FSB/HTT affect the PCI-e bus speed? or is that locked like pci/agp usually are?

If the CPU core running at 234mhz is fine depending on cooling, then I'm ok there. Gonna run a XP-120 with a 115cfm/43dba 120mm Panaflo and of course AS5

So that's all I'm wondering now, if PCI-e bus is affected and if the 3800+ Venice internal core clock will run ok at 234mhz.


Thanks for your response MustISO

 

[hippotautamus]

A divider will allow you to maintain 2.8ghz with your CPU and push your ram higher, without messing with multipliers anymore. However, most VX won't go a lot higher than 260 (in fact, the AT reviewer got it up to 269 at 3.6v)...and highest mem performance is usually not at this speed, so dividers are less important for VX. High ram speed isn't necessary when you can do DDR533@2-2-2-6 and destroy ALL competition lol