Does DDR2 ram @ 800Mhz limit a 1066 fsb cpu?

I'm looking into a sony vaio fw with the following specs

P8800 cpu @ 1066Mhz fsb
4gb ddr2 ram @ 800Mhz
500gb 7200rpm HD
1gb graphics w/ 1080p screen

will the speed of the ram limit the fsb of the cpu in any way?

Not that it will prevent me from buying it at all, just curious

Thanks

 

much depends on how the mobo bios runs the chipset and cpu. without that info, everything is speculation.

 

how would i go about determining this for my specific case?

 

It use to way back in the day. Modern day chipsets now seperate the FSB speed from the Memory speed with dividers.

 

Doesn't matter, the CPU can't utilize the full memory bandwidth, so you won't be limited by DDR2-800.

 

^what he said.
Another example is if you buy a cpu with higher fsb than the chipset can handle. the chipset will downclock it.
Same with ram, if chipset can handle only 667mhz, a 800mhz stick would be downclocked to 667mhz. Some might say to go ahead with a 800mhz!

 

Thanks guys, question answered

 

That's what we are here for. We are glorified Wikipedia articles.

 

Your real FSB is 266mhz and the ram is 400mhz.
So as you can see, you have plenty of ram bandwidth.

 

Having slower memory will not slow down the processor frequency.

 

Ok, now i feel stupid because I knew this but didn't make the connection...

 

533 ram would be the correct match for a 1066 processor, not that it's required of course.

 

Don't feel bad. I stuttered in a meeting with about 15 folks yesterday. I felt like a 5 year old that just learned to make complete sentences

 

I remember reading that the pm45 is not anywhere near maxing out the bandwidth offered by the DDR2 ram.

 

It's the CPU that no where near saturates it.

 

That was true with older processor architectures, but that is not the case with current Intel processors. Not sure about AMD, but I would imagine that the FSB/RAM ratio does not have that much of an impact on current AMD processors either.

 

Why is the CPU FSB cut in 1/4 and the RAM speed cut in 1/2?

Also, I see C2D CPUs with DDR3 1066 RAM...so what's the point?

 

To get more money out of you FSB has 4 transfers per clock cycle hence it transmits at 4x the speed, while memory, specifically any DDR ( double date rate) has 2 transfers per clock.

 

So it's a complete waste of money for anything above DDR2 800 with C2D?

Also, does this apply to mobile i7? And, am I dense, or wouldn't it make more sense to provide 3 RAM DIMMs for i7 laptops? Or are the 3 channels built into each stick? (sorry, I'm pretty ignorant of this stuff)

 

DDR2-533 would be sufficient for C2Ds. Notebook i7s aren't triple channel, hence why dual channel kits are still offered.

 

If the laptop supports faster RAM, yes it will be useful. It is worth the money? Perhaps not. But it would increase performance a little bit.

 

Yeah I'm wondering this as well. My Dell SXPS 16 has DDR3 1066 installed... I was always thinking why? The memory is massively being bottle necked with a C2D P8600 in it isn't it???

 

well i doubt it will.. ur processor has 1066MHz FSB so there should be no problem....

 

There's almost no such thing as an FSB anymore. Memory sits on it's own bus with the memory controller, which is usually the limiting factor (which is why the memory controller moved to the CPUs on AMD chips, and is moving to Intel CPUs now).

There's a reason a lot of new laptops these days are coming with DDR2: there's really no point to DDR3 on Core2 or Turion II CPUs. They tried for a while, but noticed that there was no performance benefit, but there is a cost penalty. Silly to pay extra for the same performance, so Core2 laptop designs started going back to DDR2.

The new Core i-series will use it, because the CPU won't have a DDR2 controller on it, but those may actually see performance gains from DDR3. AMD's procs will get a DDR3 controller next year sometime. But for right now, servers are the only place DDR3 makes a noticeable difference (and trust me, there is IS noticeable).