Memory Speed versus CPU Speed

quain · Jul 31, 2008

I'm pretty new to system building, so I appreciate your help and patience in advance for my questions.

I'm trying to upgrade my one year old system with some new RAM and I'm wondering what speed of RAM I should select, DDR2-800, DDR2-1066, etc?

The CPU I'm pairing with is C2D E6750 Conroe 2.66GHz. Can someone explain how I can determine what memory is fast enough for this? Right now, I'm considering PC-6400 (DDR2-800Mhz), is this sufficient?

Thanks.

smartel7070 · Jul 31, 2008

http://processorfinder.intel.com/details.aspx?sSpec=SLA9V

So your cpu runs at 1333mhz fsb and 2.66 core clock.

1333 / 4 (quad pumped) = 333 mhz real mem speed * 2 (DDR) = 667mhz memory

So 667mhz ddr2 mem is what you need. Given the price on 800mhz memory I would go for that, it would give you some headroom if you ever want to overclock you cpu.

Hope this helps !

pbrigido · Jul 31, 2008

Nice reponse smartel, you are right on the money. I agree, 800Mhz should cut it. The real question is how much RAM do you want? If you have a 32 bit OS, 2GB or 4GB should suffice...even though the 4GB will be seen to your system as roughly 3GB or so. If you have a 64 bit OS, 8GB isnt a bad idea, especially with the price it is right now.

quain · Jul 31, 2008

Thanks so much guys for the comments. Right now I have 2Gb of RAM, so I was basically considering upgrading to 4Gb or 8Gb and running 64bit OS.

gaiden · Jul 31, 2008

quain for sake of consistency get either a pair of the exact RAM models as you previously owned OR a brand-new kit of 4gb or 8gb RAM. If you aren't sure about 64 and decide to do 32 now i suggest you getting 2x2gb (2 sticks)RAM kit so you can get 2 more sticks later on and make it 8gb if you ever decide to give 64 bit a try.

gl

pbrigido · Jul 31, 2008

Anytime. Here is an article by Toms that goes into depth the advantages of having 4GB and 8GB. Personally I enjoy using 8GB...with not having to use a virtual drive, your computer will gain some extra benefits in terms of speed. Here it is though, it's a very good article.

http://www.tomshardware.com/reviews/vista-workshop,1775.html

kman7607 · Jul 31, 2008

How do you determine the divisor of the real speed equation? How did you know that it was quad pumped? What other types of "pumping" might be used in calculating real mem speed?

smartel7070 · Jul 31, 2008

kman7607 :

Those are basic numbers related to the Core2 architecture. I didn't determine anything ... Intel did !

ironsung · Aug 1, 2008

smartel7070 :

wow... for the longest time, i thought the divisors were based on the number of cpus... i mean i never researched anything cept q6** and q9** series quad cores... and when i was doing my calculations for the optimal fsb/ram ratio, i figured the 4 in 'divide fsb by 4' was due to the quad cores.... so naturally i assumed the e*** series dual cores were divided by 2.... never really thought about it, but now that i did.... doesnt make sense.... BUt everything makes sense now.. hehe

:kaola: