choosing proper RAM to go with FSB/CPU?

Picking up a laptop with Q9550 with 1333 mhz FSB. RAM supported is up to 8GB of DDR2 667 or 800. Which memory is best for this setup?

Since the FSB is really 333 x 2 x 2 = 1333 mhz and I/O clock for DDR2 667 is 333 ,then the FSB to RAM would be synchronized 1:1.

BUT would the system perform better with DDR2 800, even thought the FSB:RAM isn't synchronized 1:1, because the DDR2 800 is faster and can make up that?

Looking forward to your thoughts...Thanks

 

I don't think you will see a big different is ram speed(mhz) compared to ram size(gb). so i would go with 8gb if i had the money.

 

Whichever you like. Its not gonna make a noticeable difference in performance. And if its the D901C, it'll address around 6.8GB, and not the full 8GB.

 

The D901C only supports up to 6.8Gb of memory because of chipset limitation. Going with 8Gb (2 x 4Gb) of Pc6400 will be your best bet at getting the highest performance from your system.

K-TRON

 

What is this "chipset limitation" you speak of? I have yet to hear a definitive answer to this. The bios will recognize 8GB, the chipset can address 8GB, so where does this limitation come in?

 

Memory Hole-Remapping is disabled in the BIOS most probably. That's the only logical reasoning for it.

(The P965 does address the full 8GB with memory re-mapping enabled in the BIOS)

Search the Clevo forum. There was a thread on it.

 

Yea its strange because Sager tech support will only say "chipset limitation" and won't comment on how much ram the bios will see. But xoticpc, powernotebooks, prostar, and avadirect say the bios does in fact recognize 8GB. Straaaaaange.

Anyway...I got this thread off topic...

 

My mate's desktop (P965) recognizes the whole 8gig with memory re-mapping enabled, but it causes the video drivers to crash occasionally, so he gets about 7.4GB addressed with the option disabled in the BIOS.

Probably memory re-mapping buggy on the D901C as well, so the options is disabled and hidden from the user in the BIOS.

You can go for 6GB, or go for the PM45 notebooks.

 

thanks for the insight Andy!

 

i'd go for an overclock the fsb to 1600mhz which would increase the clock to 3.4ghz and go with the pc2 6400 ram... fastest cpu and ram speed, and a 1:1 ratio...

 

Would you recommend set fsb or rmclock to OC the fsb to 1600? Been reading up on the 901c (NP9262) and OC'ing and seems like most haven't had the proper PLL to use the OC utilities.

 

The only OC I know for the D901C is the Q6600 (G0) pin-mod, which boosts the FSB upto 333MHz, and the CPU frequency to 3.0GHz.

Forget about this memory multiplier thing.

DDR2-667 or 800, there is not going to be a noticeable difference in real-world performance.

 

ok thanks for pulling my feet back to the ground Andy

 

ok DUMB question...since my fsb is 333 * 4 = 1333mhz and if I were to install ddr2 800 what speed is the memory actually running at?

 

Depends on the divider. Running at stock DDR2-800 speeds and stock CPU speeds the divider would be 5:6, would mean memory is running at 400MHz while CPU is running at 333MHz.

 

800MHz..
The actual I/O Clock is 400MHz.

 

thanks a lot guys! cleared up my confusion