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Quad core conundrum (FSB vs memory speed)

Last response: in Motherboards
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January 9, 2009 10:12:46 AM

Hi,

I'm planning to build a new Intel quad-core mid-range machine from scratch. I'm looking at either:
Q6700: 2.66Ghz, "1066Mhz" FSB (266.50Mhz really, as it's quad-pumped)
Q9550: 2.83Ghz, "1333Mhz" FSB (333.25Mhz really, as it's quad-pumped)

I'm going for a DDR2 Motherboard. The DDR2 is 1066Mhz (or 533Hmz really, as it's DDR). With the Q6700, that means the FSB and memory buses running almost synchronously (Well, 2:1 ratio so every second cycle). However, with the Q9550, I'd have to run them at a ratio of 8:5 (I think?).

I've heard running synchronously provides big benefits. Running at 2:1 is essentially synchronous. Will the benefit of a faster CPU be wiped out by the (slight?) performance hit of running at 8:5 ratio? It's a £100 more or so, so I'd like a decent jump in speed.
Anyone help greatly appreciated!
Thanks.
January 9, 2009 1:25:10 PM

I would chose the Q9550.

When folks say , synchronous, they mean run the memory at the same speed as the Bus Speed. This will only pertain to you if you decide to overclock.

Essentially: 1:1 is synchronous, FSB : DRAM. So lets say if you ran it at 1:1 with no overclock on a Q9550, your memory will run at 667mhz. Once you start to overclock, the low memory speed allows you to reach higher overclocks without causing instability.

@400mhz bus speed: memory = 800mhz, CPU = 3.4ghz
@450mhz bus speed: memory = 900mhz, CPU = 3.8ghz
@500mhz bus speed: memory = 1000mhz, CPU= 4.2ghz

Real world, you won't notice much at all. In realtion to gaming, it may be a max of like 3-5fps. But because in gaming, your frames drop and rises all the time, you won't notice it.
!